The only 'report' I have seen regarding the assaulted guy being a peado was in a 'newspaper' with the banner TR, (immediately raises the question of it's originator), as the name of the publication.
No other news reports have anything to say about the victim other than he was assaulted by this Yaxley-Lennon, (aka Tommy Robinson), bloke.
If the 'victim' did assault the young girl then her father, or indeed any member of the public who witnessed the incident, has the right to use reasonable force to restrain him until the authorities arrive. Reasonable restraint! The clue is in the wording. It does NOT mean you can assault someone by punching them. It means you may hold on to them and, if necessary, LOWER them to the ground in an effort to aid your detaining of them.
As told to me by an ex police officer.