>there's no reason for them not to tax the UK profits of EU companies, is there?
Amazon will claim not to make any profits on physical sales and since the AWS server farms aren't in the UK any profits on them are nothing to do with the UK govt.
Microsoft will claim the same with Azure while demanding a tax rebate for any UK saless to keep jobs in the UK.
Google will book all advertising sales in the USA - the post Brexit UK isn't about to impose an embargo on USA firms.
