Jay,
I assume from your post you are not in the LVA or a Public House Managers Union which you should have been.
I have run pubs for 30 years in the past and have had many problems with drunken/violent and abusive customers against myself and staff.
Firstly, has the person made any accusations or complaints to the police about you about the incident and what injuries did he suffer apart from being unconscious?
Was he drunk, abusive or violent to you or the staff?
Have you got any customers/staff as witnesses, or CTR cameras?
Is he a local in the area with a history of causing trouble, most are?
The only problems these days Jay, to when I was a landlord is that the courts are to soft and all this bloody human rights law and allowing the drunken public to sue for injury even though they committed the crime and botox to the business people who are trying to earn a decent living for their family's.
I have been taken to court twice for assault, once in Dover when I was found not guilty and the other in Newmarket when the magistrate threw it out of court and gave my accuser a £150 fine for wasting court time ;-)
If you want any more advice Jay, ask me, as I feel very strongly about the future of pub landlords of today especially with a family, trying to make a decent living in this violent society!