Nickyjames, with regard to self defence, from what I understand (and I am not a lawyer so do your own research), it largely comes down to "reasonable force" and a bit of good old common sense.
The size of your attackers will also be taken into consideration compared to the size of you. If you are a small fella and a big guy starts swinging at your head, I would think you're well within your right to swing back at his head - but run on the first opportunity you get so it does not escalate.
If you're a big fella and you beat a little fella up, I would suspect strongly that the judge will throw the book at you.
I was set upon by seven men once in a case of mistaken identity. I did what I had to do to get out of the situation and then ran and hid. It's one of few times in my life I thought I may actually get killed.
