'Babysit' is pretty much what they do end up doing. It is everyone's right organise a gathering in order to march, provided they consult / inform the police at least six days beforehand.
The police, however, do have the right to move a march if they fear public order offences.
And therein lies the rub. They actively advertised that they were coming down to cause, provoke or indulge in trouble. That ought to be enough for the Police to say 'we can't guarantee public safety' and therefore ban - or at the very least, move - the march.
If the EDL had said 'Celebrating...