For future reference, Hart Wildlife in Alton definitely care for injured birds.
I ended up contacting them today and will be dropping the dude off tomorrow. They can provide treatment and rehab etc but they did say if the wing is a really old injury and hasn't healed correctly, then the bird won't ever fly again and that's detrimental to its life (cat attacks etc) - And it's not advised to keep a wild bird indoors either

I've also noticed that when indoors he just stays in one corner, whether in the room of in the large box with food etc, but then randomly will full of energy bouncing about eating and stuff. Thes ebirds in the garden are always moving, never still, so I guess being indoors makes them get extremely bored/lonely.
Let him out earlier and he tries to fly but ends up gliding down, can climb really well and has loads of speed on the ground, so certainly has regained all that energy. Also these things poop a lot!
Look at the wing, it looks the same as the working right wing, but it doesn't retract properly when you pull it out then let it go like the right one does:
Oh yeah he's got accustomed to humans now too, lets you pick him up, head rub, beak move etc. Kinda neat. But then randomly he realises he's a wild bird then runs ioff jumping and trying to fly until you go get him again
Hopefully Hart Sanctuary can give the correct care though.