A big thanky ou for all the on and off list responces to my query. It was the Cranks not the pedals and the issue was a little bit of rotation of one crankrelative to the other. On lookig more closely it semed that one cotter had worked loose at some point (probably after I douse avery moving part except the brake pads in oil) A couple of firm taps with a spanner and a little nut tightening have eliminated the problem.Sorry for wasting all your time, but thank you all very much for the suggestions for Cotter removal (both with and with out the proper tools), I shall need them if/when I get around to upgrading this bike to a 10 speed.