90% whistle free! Thanks for your reply, I have removed the rear discs ground, cleaned & greased etc but at that point-still whistling.
After my visit to lex-tek autos yesterday, Dave found its the o s f wheel bearing seal was dry so that was causing the whistle. He squirted some duck oil on to the seal after removing the disc. So booked in for a new wheel bearing next week & hopefully that's the end of that.