Try to get the Section 3 Public Order (Affray) dropped to a section 5 (causing harassment/alarm/distress). Your account of events should be clear on the CCTV and you need to play on the fact that you were trying to pull your friend away.
If you get it dropped to a section 5, because you have no previous convictions, you could be offered a caution. This is kept on record but is not a conviction and is stepped down after 5 years (you dont' have to tell potential employers you have one).
To get a caution, you must accept guilt and be remorseful. But DO NOT PLEAD GUILTY unless a section five is offered. You do not want to be going to court for Affray on a guilty plea - you could end up with a conviction. Although you may have accepted responsibility in interview already??
Get a savvy lawyer and try and get a Section 5 Public Order caution.