Although stranger things have happened I would be very surprised if he escapes without an immediate custodial sentence, especially bearing in mind the circumstances in which the offence was committed.
Violent Disorder (section 2 of the Public Order Act) is a serious offence which carries a maximum of five years custody. Here’s an extract from the Magistrates’ sentencing guidelines for the offence:
These offences should normally be dealt with in the Crown Court. However, there may be rare cases Involving minor violence or threats of violence leading to no or minor injury, with few people involved and no weapon or missiles, in which a custodial sentence within the jurisdiction of a magistrates’ court may be appropriate.
The matter has already been sent to the Crown Court which indicates that Magistrates did not consider the matter trivial enough to be dealt with in the lower court. In any case, even if it was retained in the Magistrates’ court the guidance still suggests that only custody is appropriate.