Thanks for help we made another clip from the part we used shifted it by 5 frames exported as new QT re-imported problem solved but I am sure you are right about it being TC problem.
The shot in question is ProRes as is most of the sequence there are a few ProRes HQ 25fps and Pal-DV 25fps shots later in sequence but everything up to this point is full HD ProRes 25fps
Hit the nail on the head interestingly shots either side developed feild issues sorted by field shifting bit strange but who cares if it works thats ok with me