Right, I got a friend of a friend who is a dub nut to help me change the mount at the weekend, and it has transformed the car completely! Every wobbly, rattly issue that it had before is now gone and it drives beautifully. He did mention that the front engine mount could ideally do with changing too but it probably still has a bit of life left in it. All in all, i'm well pleased! as soon as I have decided what issue to tackle next, i'll put another post up!