I have tried the same dummy booking on two AutoEurope websites: .com and .co.uk for a one week rental from BHX in June.
For identical hires (as near as I can tell) the weekly rate is about $200US higher via the US .com website than via the UK site. I have gotten as far as inputting a US address on the UK site and it was accepted, taking the booking process all the way up to "pay now."
Is there any reason that, as a US resident/US licensed drive I should use the US site and not the UK site?