Hi Everyone, Almost forgotten about my original post! Anyway I thought I'd post an update in case anyone else has this issue... The knock came from the passenger rear whenever the car went over a bump in the road. I removed the shock absorber and it looked fine, remounted it, drove down the road and the knock was still there. By luck my neighbour's son works for Ford and was next door that day so I asked him around to take a look. He checked the shock absorber mounts and they were OK and he said he had come across this issue at work with a couple of customer cars. It turns out it was the rear seat latch knocking. He said the garage fix for this is: Fold forward the rear back and this will expose the metal hoop that the seat latch engages on. Simply wind a couple of turns of PVC tape around this where the latch grabs it. Done! It's now six months on and it's been perfect ever since. Sounded just like the shock absorber, but it wasn't. Hope this helps someone.