Rear Diff Mount.

I have had the centre rear axle diff mount replaced 3 times in 6 months and each time the rubber bush inside splits and the mount fails causing a lot of play in the rear prop and a clunking noise when going round corners etc. I have recently had the rear prop and VCU replaced but the problem keeps coming back.
Has anyone had this problem before and any ideas why this mount keeps failing? My mechanic is suggesting there may be a problem inside the diff which may be causing more strain on this mount, the other 2 axle mounts are fine.
Any ideas or comments please?
Steve ( 2000 X Reg TD4 Auto)

If someone watches the diff (safely from one side) as you pull away what happens? Did you replace the bush with a good one? £18 from LR. There's some cheap ones about which don't last long. Could the mount have split when fitting it if forced into position too hard?

Its when I turn sharply round corners i was getting a "clunking" sound, which was caused when the centre mount rubber split in the middle causing a lot of play in the diff and rear axle. Yes, the mount just replaced was from Landrover, so is a quailty part. I shall just see how this 3rd one now goes.
Thanks

is it maybe worth fitting poly diff mount bushes