Over the last couple of days I've noticed a heavy knock comming from the drive train. It is intermittent when comming on or off power and sometimes happens quite severely when changing gear. It was at it's worst in the cold of this morning. The return journey seemed to be pretty clunk free for the first five miles. It generally gets worse as he journey progresses and sounds like it's comming from the RH side. I've noticed a small quantity of oil on the road where I park, so I'll top it up tomorrow and report back. My oil can is 30 miles away in another house.