The cheeky b@$t@rd$!! The only reason your window is broken is because they didn't install it properly in the first place! Outrageous!Still not resolved as Hobby UK have told us as our window is broken they do not have to pay for it because it is out of warranty but have offered us a 30% discount! As yet they haven't actually told me how much.
I see that pyro has kindly provided a wealth of information on the legal side of things. There is no reason for you to have to pay a penny.