Buy yourself a can of tyre weld quick as poss, just in case the worst happens.
I have had a couple of cars in the past with this problem and it is possible to get them off. There are various tools on the market now that claim to be able to remove them, they are like a universal gripping socket thing !!! Not tried them so don't know if they work.
I found the best way was to try and force on a close fitting socket or drill the head off the bolt, but it depends on what type of bolt you have and how hard it is. The standard Vauxhall ones have a rotating outer ring to prevent you from getting a socket on there, you could try cutting this off with a dremel mini grinder an dthen getting a socket hammered on there and hope its not too tight.
Best of luck Mark.