[batty]

A quick update from me - I had the lower trailing arm inner bushes (oil-filled) replaced, and for a while (honeymoon period I guess) the noise had gone. But it's definitely back - it's hard to say after how long. It still seems intermittent which is strange. Sometimes it knocks over the tiniest undulations (car parks etc.) and tends to keep knocking for that journey. And sometimes it's perfect for the complete journey. It doesn't get on my nerves, so I'll take it to the dealer again when I have time.