well the lack of replies actualy answers my concerns :-)

Have spoken to the company concerned who have requested i return the bush for examination, since they cant remember any other failures. Surprisingly the bush was easily removable fron the trailing arm where as the originals had to be burnt out in the absence of the volvo tools.

Either way the car passed its test and is legal again for another year so for the price of an aftermarket bush i wont be too down if they come back and say they are doing nothing about it. The car is handeling much better again and the rear is sitting at the correct height instead of looking a little saggy.