I can imagine that certain UK admins will throw a block on you becoming involved under the pretext of "trolling". I get the impression that the people concerned really don't believe they are promoting racism and others may just be too ignorant of the subject to see it.

What may be a better route in, is to join your local IMC and then become a UK admin. If you have already used your real identity, you'll need a new one or they will see you coming.

A further idea may be to take direct action against Indymedia UK by raising these issues with regular contributors, regional and international IMCs and seeking a boycott until the regulations are applied universally.

They could also be picketed, excluded and disabled at any events they try to attend.

Thanks for speaking up against racism.