Do some thing about it!
If you feel that XL have a case to answer in law then do some thing about it, take advice from the CAB or your union rep, if the union thinks you have a case they will back you.
It is very easy to sling mud on this forum but the real test of your case is in court, if you are in the right they will probably not take it to court and will offer you a pay off......... now do you wan't to stand up for your self in the face of this "unreasonable" company? Or are you just letting off a lot of hot air on a forum in which the company can't defend its self?
In short are you man or mouse?