Graham
Thanks for your help. My independent chap has already stripped the shocker and spring and re-fixed after bench testing and still no joy. He was confident it was the shocker
We have used a stethoscope and he is now stripping the "control" arm that acts , I think, like a rear anti roll bar as the squeak was more pronounced when using the stethoscope on this.,
Fingers crossed he finds it. If not it's replace all rear bushes and there are a lot of them