What leads you to think that American and British numbers are so different? Have you heard many EA-aligned Brits express support for the Conservatives, particularly across multiple election cycles? Is this mostly a guess based on British Conservatives being (generally) less right-leaning the American Republicans?
I asked a few EA-aligned Brits what % of EAs they think voted for the Conservatives. I suspect this number is not robust across election cycles, but I’m also not confident that mean regression should be the default hypothesis given a) how young EA is and b) modern British politics seem to be in somewhat uncharted territory.