Thanks Eddie. I thought I had not seen it.
Your solicitor will advise you properly, Isharp, but he may suggest that you plead not guilty on the basis of self-defence. Although you struck the first blow, if you can show that you had an immediate fear being assaulted and that hitting him was the only way to remove the threat then you are entitled to use reasonable force. As far as the second assault goes (by the girlfriend) the same principle applies. But it is really very difficult to advise you without all the details (witness statements, etc.) and that is what your solicitor will do.
Whatever the outcome, whether you plead guilty or are convicted following a trial, the sentence is not likely to be severe. The offence is aggravated because it is seen as “domestic violence” but it otherwise sits at the very lowest end of the scale of seriousness. I would not be surprised if you were given a Conditional Discharge.