Diff mounting plate help?

[Poledriver]

Had a problem today with my Cerb, whilst having a 'spirited' drive.
With power on she was fine, lift off power and there was a lot of vibration/rattling from the rear. A quick look shows what appears to be a bolt (maybe more than one) which goes through a mounting plate and into the diff body has sheared!
Anyone had experience of this?
Any other problems which could have occured?

The diff is moving when power applied/removed. I haven't had a chance to have a proper look underneath yet but I'm hoping it's going to be a simple matter of removing what remains of the bolt (simple???), straighten the mounting plate and replace the bolts(s).

[Ireland]

I made flitters of the rear diff bush on a track day and it's really difficult to get in at that rear mount with the diff in the car.

I'd say, if things are as you reckon, you'll have to take the diff out to fix it.