Hi RGItaly,
If you are selling items in to the UK over a value of £135 then you will only be making taxable supplies in the UK if you are the importer of the goods in to the UK.
If you are the named importer of the goods then you will be making a supply of goods within the UK and as a non established business there will be a requirement to register for VAT straight away.
Please see guidance below:
9. Non-established taxable persons — basic information.
Thank you.