Self-employed cash basis IT expenses

Hi, I think this comes out to about the same answer so I'm curious rather than it really mattering (I'll be close to the 1k and may just claim the 1k to keep life simple). I believe that in my situation, if I have purchased a device (laptop, phone, etc) I can fully account for it as an income tax expense, and if using it for dual purposes (work and personal) I should pro rata the cost based on the % used for work. In another bit of tax guidance I have also read that in some cases the maths can be that if, say, a £600 device would have been sufficient and my likely purchase for personal use (e-mails, documents, browsing) but my work (geospatial) required a £1000 device, I can instead of pro-rata, claim the "necessary improvement" and claim the £400. Does that apply in my case, theoretically? And if it does, do I have to treat all devices similarly, or if I have a laptop as above, and a phone where I'd have bought the same one either way, I can do the above on the laptop but the pro rata on the phone? As I say, probably theoretical!

Hi,

You can find guidance here:

Claim capital allowances

Thank you.