As per the law you cannot be charged with affray( or any other offence) for using reasonable force to defend yourself. If two persons are arrested for affray, one , both or neither may be charged. It depends on the circumstances and the evidence. There will be cases where the evidence is such that both parties are charged because it cannot clearly be established what has occurred. This is possibly where both parties will be charged and the courts will be asked to decide. By that definition persons who are innocent could be charged and may be even convicted( see my earlier post re miscarriages of justice). It is known for innocent people to get convicted, that's a separate topic I dare say. As also previously stated I took it that your first post re persons being charged with affray implied using reasonable force to defend yourself could lead to a charge. This is not the case, or shouldn't be. I hope that clarifies matters for you.
Edited to remove the old news used as evasive stuffing. Begs the question, but please don't waste my life answering, as to why you posted that abusive drivel earlier in this thread.