On one of my cars, they're starting to peel and disintegrate, so it's also something I've been looking at for a while.
I'm guessing the subframe needs to come forward to be able to remove / fit them? With the fuel tank quite hard up against the back of them, there's little in the way of clearance.... or am I just missing something?
car on axle stands, jack under the diff(not necessary, but why take chances), undo the 2 bolts that hold each 'horseshoe' to the car, and the single bolt that attaches the aluminium centre to the diff. The mount should come off in one piece. If you do one at a time, the diff won't move enough to prevent you from just bolting a good mount in place.
Access isn't an issue, even on an estate with a towbar.
To go back to the original post, there's nothing special about any of the three bolts. Which if I remember right are two short M10s, and one longer M8. But that could me M8 and 6