How do I remove the plastic cup behind the fog lights on a Bug?

I've gone to swap the foglights and the metal bracket behind has rusted through. This means the one of the bolts is just spinning. I've tried to clap what is left of the bracket but the bolt is rusted to it and it just chews up.

Can I therefore remove the whole black plastic cup, so that I can get to it? If so, how does the plastic cup detach from the bump? Just it just needed to be levered and popped out or is it attached in some other way. Really don't want to break it!

 

Remove the bumper. The brackets are held to it by being slotted in from the side, no fixings.
new brackets are cheap, I Hammerited mine before fitting.

Bumper off is ten minutes once you know how, a search on here will provide instructions, or ask that question specifically. Mine's a classic, which is similar, but not identical, so I'll leave that to someone else.

 

I think I'll get it up in the air and take a Dremel to the bolt, as it might prove tricky disconnecting the lead from the lights.

Are the brackets available new. To be honest I was thinking of just using stainless bolts, washers and nuts, as I'm not a fan of captive nuts in general. That's how I've refitted the bolts now anyway.