Username

I opened up 4 email accounts with made up names and then signed up to each bookie with a username based on that email name. just try and avoid signing up to related bookies with the same email address (especially paddy and betfair).
be aware that you will have to use your bank card and prove your ID, so don’t actually try to be someone else, just use variations on a theme. (for example densman6@yaddayadda, thedens@yadda. bigbaddenno etc) Obviously make sure you have a strong password.
HTH

betfred/totesport are the same too, so pick a different variation for each of those.

There is some relationship between boylesport, apollobet and some say betmclean as well. So might be an idea to have a different email there.

They can still link by date of birth, address, ip, payment method etc. So not sure how effective separate email addresses will be – but for little pain it might help.

I wouldn’t take it any further than that though. Spoofing your home address or date of birth etc could land you in more trouble. They could have you for fraud and decide to hold your balance.