Yes, services* purchased from outside the UK would be reverse charge, this means you treat the purchase as a sale (sell to yourself) and the purchase therefore counts towards the VAT registration threshold.
For example, your UK turnover is £70k. You buy in consultancy and legal services from overseas and the value of those purchased services add up to £20k. £70k + £20k = £90k and therefore over the VAT registration threshold, your business would need to register for VAT.
Remember the threshold is a rolling 12 month calculation, thus include your overseas purchases of services in with your sales income each month to see if the threshold is breached.
*you should also read the Public Notice 741A section 6 to better understand the default rules for services.
To reiterate, if you sell something on eBay for £12 then your net sale (yours to keep) is £10 and the £2 is VAT which you pay to HMRC.
eBay will not actually send you £12, they will deduct their fees, lets say it's £4, so you receive £8 into your Paypal/bank account. The value of your sale is not £8, it is £12. As long as you are declaring output tax on the £12 (£2 VAT) then that is correct.
If the goods are in the UK at time of sale, for VAT purposes the place of supply is the UK. When you export those UK goods to USA/Canada, you are making ZERO rated sales in the UK. Zero rate is a rate of VAT and therefore counts towards the VAT registration threshold.
People sometimes assume that zero rate means "no VAT", whereas technically VAT is being charged but at 0%, so although to the casual eye there is "no VAT" added on top of the selling price, there is still VAT being added (albeit Nil) on those sales and those sales count towards the VAT registration threshold.
Google "MTD Bridging software", there are many different online offerings, some are free, but a paid for version may have better customer support.
You cannot file your return via the logged in VAT Account, you either use accounting software like Quickbooks or Xero or if you use Excel then you can use "bridging software", whatever route you use, the VAT return can only be filed by using a software solution. Explore bridging software as that will allow you to upload your excel spreadsheet to a special website and the website will then connect to and transmit the data to HMRC.
This requirement has been mandatory since April 2022 for small businesses, but HMRC allowed some additional time to transition but that transition time ended 01 November 2022. You will have received emails and post advising of these changes during last year.
There is no "reverse charge"* for goods in the UK, not since Brexit. Do you mean Postponed Import VAT Accounting (PIVA) where the import VAT is not paid when the goods enter the UK and you account for the import VAT on your UK VAT return as an output tax and an input tax?
If yes, then you will download each month a Monthly Postponed Import VAT Statement (MPIVS) from your VAT gateway and this can statement can act as your import record in your accounts.
*there is a reverse charge for goods if the goods are going to a warehouse in Northern Ireland, which remains part of the EU for VAT purposes and even then, reverse charge only applies between Northern Ireland and EU member states, not rest of the world.
Duty is, as you have stated, not VAT. Goods over £135 coming into the EU will be subject to import duty and import VAT. the duty liability depends on what the goods are and their origin. You are also correct, duty (import duty) is not recoverable in anyway, it is simply a tax for bringing that item into the Country. Imports will always be subject to import DUTY and Import VAT. Often the import duty will be Nil so you may not always incur duty, likewise if you are importing children clothing, they would be zero rated, so you would not get a duty or a VAT liability, but if you are selling machinery parts, then import duty plus import VAT would apply
In your example, yes, when quoting a price to the customer (or if via website), you would need to factor in the net price of the goods, plus carriage, plus DPD admin, plus VAT. It would be highly unusual to see duty at 23%, so if you see on DPD paperwork "tax" and the rate is 23% then it is more likely Irish VAT , duty rates tend to be much lower (0%-10% depending on the goods), so in your example item on website sells for £200 delivered, then we work back from that, the £200 is made up of the net amount of say £150 + carriage/admin costs of £10 (total is now £160) + import duty of 2% which is £3.20 (total is now £163.20) + VAT of 23% which is £37.53 (total is now £200.73) so in this example you have charged customer £200 all in but it'll cost you £200.73 to get it delivered, so no margin/profit on this, your advertised price should therefore be higher (ie, £210 advertised price). This is just a very broad example, not meant to be accurate but designed to explain the basics.
You may be able to register for Irish VAT but you'd still only be able to reclaim the 23% import VAT element, the duty is still a cost to you and you can't go back to the customer (or you could but could be fun). There is also the issue that the original imports did not happen under your Irish VAT number (as you didn't have one), so reclaiming the VAT element may still be tricky, freight agent may amend their original import entries, might need a discussion with the Irish VATman.
As for Incoterms, useful link here https://incodocs.com/blog/incoterms-2020-explained-the-complete-guide/ you'll not find much on HMRC website for Incoterms as its a freight/shipping thing and its not much to do with HMRC other than the Incoterms you use determines whether the duty/VAT is your issue or the customers.
Incoterms define who pays the import duty/VAT. Scroll down the above link and there is a chart/diagram about half way down, the chart has grey squares and blue squares, the colours show who pays what, Incoterms are not just about VAT/duty but also about who pays for shipping, who pays for unloading and insurance, etc. At one end of the chart is ex-works, the price you pay for the goods is the factory gate price, it's your problem to get it from the factory gate to your destination. If the ship sinks in the sea, you claim on your insurance as your problem. At the other end of the chart is DDP, delivered Duty paid, this means the price the customer pays is for everything right up to their front door.
Most people use EXWorks or DDP but there are other variations such as DAP. The chart shows you who is on the hook for what. the important point is that when speaking with your shipper, you are clear what Incoterms are in play, the shipper will then know what paperwork to submit at the customs/border
Your accountants can use this link https://www.gov.uk/vat-repayments and scroll down to the bottom where it says "fill in a form...." when they get to the page where it asks "do you have an IBAN", answer is "no" and it will then allow you to enter a SWIFT number. Australia is one such Country that doesn't operate an IBAN, only a SWIFT.
This above link only works for the taxpayers gateway/UserID, so the Accountant cannot access via their own agent gateway, the Accountant must have permission from you to access your gateway, or you can update your bank details yourself via the link and using your gateway (UserID).
HMRC rarely take bank details over the telephone, for obvious security reasons, you can also write to HMRC, which has already been given to you.
Some cloud only type banks like Monza and World First sometimes do not send the right "flag" back to HMRC's computers and triggers the error that the account can't be used. So your account may have received payments from others, but does not mean it can receive from everyone.
You can't reclaim Irish VAT on a UK VAT return.
If goods have been shipped DDP, then the seller is on the hook for the import duty/VAT and none of this is recoverable by you. It would make sense to treat the Irish recharges as no VAT in the accounts as it's not VAT you can reclaim, it's just a cost that eats into your margin.
The only way to reclaim this Irish VAT is to register for Irish VAT, you can then reclaim this Irish import VAT but crucially you would then have to charge Irish VAT to the customer and this is unlikely to be possible as I am assuming the customers are consumers (B2C) and so they've already paid the price as advertised on the website and had the goods delivered with nothing else to pay, so to try and hit them with additional VAT now would depend on your contractual T&C's.
If the Irish VAT is a small amount then it may be a case of take it on the chin and get it right going forwards, certainly make sure you know what the incoterms means, DAP means the customer gets a knock on door from courier demanding payment for the import VAT, so DAP shifts the tax liability to the customer but does the customer know when they order the goods from you that the price is not including taxes? A better experience is DDP but likely means registering for Irish VAT and then charging Irish VAT to customers.
if the errors here are large, then you need to speak with the freight agent to see if they got the Incoterms wrong and probably also speak with your firm's external Accountant.
Your services sounds like they are exempt because you are on a medical register providing Chiropody. Exempt means your income does not count towards VAT registration threshold. If you sell things other than medical services (such as books, after care creams or accessories like in-soles), these would count towards the VAT registration threshold. The exemption relates to the services of protecting, maintaining or restoring a patients health, the sale of non-prescription creams and accessories is not part of that exemption - see section 3.1 here https://www.gov.uk/guidance/health-professionals-pharmaceutical-products-and-vat-notice-70157
That notice is worth reading in full.
For VAT, only your sales matter. For profit and loss (and corporation or self assessment) tax purposes, you would of course take your sales (£90k) and minus your expenditure (10k) to work out your profit and you would be taxed on those profits but that is nothing to do with VAT.