This happened to me last year, I'll find the thread in a bit when I get on the PC.
What happens is a small bit of plastic in the catch breaks so you can't open the lid. There are three screws underneath (visible from the footwell) and also three screws in behind the top of the lid, so in my experience you won't get the box out without opening the lid.
I found that poking about behind the catch with an electrical screwdriver didn't help either, so once you're satisfied that it is the catch which is broken you need to try and break it out. Again the screw to remove the catch is hidden on the inside edge of the lid! With care you can break out enough of the catch without damaging the lid to allow a screwdriver in to pop the catch open. When you've done that you can remove the catch to allow you access to the glovebox until you sort a new catch.
Catch was just over £20 from memory.