What is the law on physical punishment in the UK?

Basically, all those things you mention are illegal, and if any marks or injuries are evident there is enough evidence of that As a family group it would be preferable to resolve your differences by dialogue, instead of resorting to violent acts. Please try not to be unreasonable with your parents or wind them up. If they continue to be violent towards you then you should seek help from an outside source asap. Your parents may need some guidance themselves, but you don't necessarily want the police banging on the door. Childline freefone is one suggestion if things get rough, but try to resolve things at home first. Good luck, and take care.