YABsoU
It wasn't a 'platform', it was a documentary.
It showed a lot of ordinary Muslims challenging them and calling them out while they stood on the street with their little stall performing da'wah.
It showed them saying that all Shias were Kuffir (not Muslim).
It had the guy strolling around Ealing pointing out good buildings to throw homosexuals from and a green to stone adulterers on once the Sharia state is here. Later it showed two of them laughing at horrible Daesh execution videos (while they ate).
It showed them with an ISIS flag and then their hugely aggressive dealing with the police when the police came looking for the flag.
It showed the really impressive members of the Southall Mosque emerging furious and scaring them off from their provocative little protest outside.
It uncovered just how extreme they were. It touched on legal proceedings against them and the difficulties for the authorities.
Not a bad small-scale expose at all, giving quite a bit of insight into the extremists but also coverage to the muslim majority they rile. What more do you want?
I completely disagree about the passports BTW. It sounds pat but it probably IS a bad idea to trap extremists with ill intent permenantly in the UK. A proportion of them would rather be in Syria. I'd be tempted to let them go, I think.