Tell me about, I'm crippled and scarred for life. I have a hard time getting out of the house, I keep having panic attacks as a result of everything that's gone on plus everything else. And these two get to walk away with **** all consequences while refusing to name the others. So much for the British justice system!
My heart really goes out to you reading this, I'm sorry you didn't get the justice you deserve. I got attacked by 5 drunk scumbags vs just me years back and luckily only got a couple of black eyes and body bruises out of it as they all ran off when someone shouted they'd call the police from a house, but I too felt some fear for a while afterwards going out. Like your situation I was massively outnumbered but unfortunately with your leg getting terribly broken it's much worse than I had to deal with.
But you've already come through a lot and were man enough to face them - unlike your pathetic, cowardly attackers. Not many people would have to guts to face them like you did. You can be morally sound in all this, they are pathetic scum that will forever have to remember they cowardly ganged up on someone and broke a major code of being a real man.
Time will definitely heal this, soon you won't feel panicked going out, but it will take time. Maybe in the meantime you could do some martial arts when fully healed if you're feeling panicky going out?
Rather than feel panic, I think you need to let some righteous anger out so you can deal with this due to not getting justice from the police, maybe even some counselling or as others have said compensation, I know someone who got a few grand from a similar beating when bones were broken.
I really hope you can get some sense of justice and closure from this that deserve.