I had the same problem, I sourced one from here.
www.absolute-tuning.co.uk/mg6-parts-1-c.asp
I couldn't just get the clip but £70 is a far better price for the whole regulator?
It was a year ago now. No problems with it. And easy enough for a DIY job.
That's good, it's not that big a job though. You can get away with only releasing half the bumper. As for the security nut I removed it with a pair of grips. It only took me 30 mins to remove and replace.
Hi Dom99
I don't think the catch is the problem? I had a similar issue. The alarm sounder situated behind the rear bumper passenger side has its own internal rechargeable battery. As this starts to fail I had it go off when unlocking the car or sometimes starting car. To fix the problem I removed sounder opened it resoldered new battery's in place and this solved the problem. There are other threads on this in the forum.