> But if you offer paid servies, collect money from UK citizens, you must have a business representation in the UK

I don't think that's true at all. You be taking payment by credit card, which doesn't require you to have any local presence.

I think your bigger risk is that you get a judgement made against you by a UK court, which a court that has jurisdiction over you is willing to enforce. I'm not sure under what circumstances that is the case, but I believe that it being the case with libel judgements has been an issue for a while (since plaintiffs can 'forum shop').