If your husband is being charged or cautioned under the Public Order Act for assault under section 20, he may even have a charge Of Grievious Bodily Harm to face. This sounds somewhat heavy handed to me and I would recommend that you get proper legal advice. A quick search shows that the max sentence is 5 years imprisonment but there are various clauses and recommendations regarding sporting events and the like. Methinks that the opponent who was injured is pushing for a conviction with the hope of a compensation claim, and I would definitely get some advice. You could try the Citizens Advice Bureau for free advice and hope that Barmaid pops up to give you some advice here on the Bank.