Sorry but I think you haven't answered the questions about the earnout element, in particular can I claim back the overpayment, does it carry interest, and do I need to structure it a certain way to go this route. All of this is dealt with in HMRC practice notes but I wanted to see if there was anyone who could shed any particular light. I have no idea why you mentioned the USA. Let me know if you want to try and tackle this or are happy that I decline to approve the answer.
You still haven't answered the whole thing. You appear to suggest that given the structure stated I have no choice but to declare and pay the lot notwithstanding that I don't expect to get it all. Can I reclaim the overpayment once the value is known? Will the overpayment to the Revenue carry interest receivable by me?
I am sorry you think it unfair, however you could have made it clear that your answer was incomplete and you would be following up. In any case you still haven't indicated if I will be able to reclaim the excess and if the repayment amount is subject to interest.