Thanks for all the suggestions - it turns out that the bulk capacitors i had on the power supply were most likely the culpret.

i manually put a bleed resistor on as suggested and voila - the problem vanished.

i will spend the rest of the week understanding what Acetronics has suggested - sounds like some good stuff there if my understanding was a little more progressed

i am now having a complely different problem, will post that next.

thx for the suggestions all.