The clamp and bolt were replaced with new on sunday with the new distributer and were tight enough to generate swarf around the base of the distributer. It looks as if the rotor arm has made contact with the distributer cap as the contact on the rotor arm was broken off (sorry I could not see that in the dark last night).
I still think it is more than a bit strange that its the second time in six miles that the distributer has rotated or broken off the drive pegs. I had a quick look in daylight today and there doen't appear to be any other damage other than the rotor are . I think I need to look a bit deeper before I risk starting it again. I'll keep you posted as to what I find.
Thanks for all your advise I will check everything you have suggested.
Daz