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.