Thanks for that Mick,in the mean time i thought unlikely but not impossible that it could be just the light switch and agreed with customer we had to eliminate that first and sure enough it was!
Problem now is that the o/s rear side and brake lamps are interacting and the centre stop lamp is pulsing?also rear fog lamps come on dim with rear lamps,have checked the rem unit for signs of damp but looks perfect as do all connections.
just like a bad earth but these work with switched earths i am thinking rem unit although didnt have these symptoms when car first came in
Any idea how i could test further? would a unit off another s type plug in and work?

thanks

Graham H.