thought i'd let people know how this problem went on....... basically i went and bought a kmc kool chain a standard size and tried that before buying anything else. unfortunately the problem still persisted. the idea of not enough chain wrap around the freewheel was next on my list . my friend gave me an old shimano duralliere and wella! it worked. so i decided to buy a double chain tensioner. it came yesterday , its the tensile one with the gold jockey wheels...... now however , although its setup perfect it seems to make abit of racket when i pedal. bit like gears when their not lined up correct. i cant work out whats up with it.... its lined up perfect, its the long arm version which is what i needed, the hanger on the frame is stright, the chain is not rubbing on the inner cage the chain passes through, and the top jockey wheel does not touch the teeth on the freewheel. why does it sound like this? god knows!!! any help much appreciated.....