Whilst I agree that businesses should be protected, and that something like a cleanup bill would be a good idea, I do think that this is a case of punishing the many for the acts of the few who watched 'V for Vendetta' and thought it was a documentary. To be honest, Boris is highly unlikely to say 'Yes' anyway, he's coming up for re-election, and it'd be a really silly political move.
The problem is that the people causing the trouble weren't really associated with the TUC at all, they were a fringe group that seem bent on destructive and violent behaviour, it seems more for the hell of it than any real understanding of the situation, the riots were taking place some distance from the actual march. What we really need is a better system for discouraging vandalism, simply telling people 'You can't protest here' is more likely, in my opinion, to inflate the problem than reduce it. At the moment there is only one place in the UK that you cannot protest, and that is on Downing Street, try to expand that area, and I think it will cause more trouble than it solves.
Edit: The BBC clarifies a little, that companies want
violent protests routed away from the shops, which is kind of amusing, since it makes it sound like the Police always have a choice where the rioters go...
http://www.bbc.co.uk/news/uk-england-london-12886784