Update on poly bush diff mount. I completed a couple of hundred miles on the poly diff mounts but there has been a constant drone/buzzing noise/vibration from the rear end on trailing throttle. I wasn't sure it was the diff mounts, as I replaced them with poly bushes before I even drove the car, so I had no reference point as too whether the noise was there before. In the meantime, a diff mount with what looked like reasonable bushes came up on Ebay for a good price. The mount needed cleaning up but the bushes weren't too bad. I thought it was worth a try as it's only a half hour to change it. What a transformation
. The noise/vibration has gone. The slight knocking when going on/off throttle quickly has also gone. The car feels so refined, the whole powertrain is smooth and quiet. I think a set of the Monster Sport parts will be money well spent. Perhaps a few people who would like them ( myself included ) could get together and pay for one set of postage only. My conclusion is that poly bushes might get the car back on the road but the refinement will be missing, though softer poly bushes may work better than mine.