Suggest using a service called ReShip. You have the item shipped to Your Name at ReShip Address, USA and it will be reshipped to your address in the UK. They have a depot/warehouse in the USA, in Canada and the UK. So you can have an “addresa” that is one of their depots:
The only challenge can be paying for the item, if their online ordering system only takes credit cards (no PayPal) and the “billing address” (as distinct from the shipping address, which will be ReShip) form only allows the input of USA addresses. In this case, you can order by phone, after practicing your American drawl (say “ya’all” 10 times in the mirror).
I live in Canada and it drives me nuts that so many US vendors don’t recognize that there is a large global market outside of the USA!