1) I'd Consult your GP or Hospital for their advice, it'll lend weight if you decide, rightly. I think, to stay at home, but as for going to work, you don't say what you actually do, can you get to work?, and if so, can you do the job?, although in my firm, even htough they prefer you to return )light duties etc), if your sick at home, they can't do anything about it.
2), have your emploers asked you to return, if so, ask them where you stand should returning to work agrevate your injury in any way.
3) I broke my ankle a few years ago, took three months to heal, (still have the pin in), I play Table Tennis to a fairly high standard, so I would think if you look after it, you should play again,
4), Compesation, all I can say on that, is see what your union say, but if the drainage channel should have been covered, it sounds as if you have a claim,
6), If you do claim, and its a big company, it'll be a long drawn out affair, but if you have a good union rep, he/she will see that they don't.
Not much, but I hope it helps.