Its been a while, but thought I would share the fix to this problem in case anyone else was suffering from the same issue.
Basically it was the tyres. I had miss-matched tyres front and rear (fronts matched. rears matched) same profile (205/55/16) but different brands. I was trying to get by on 2nd hand tryres till I could get a new set of rims.... But I ended up putting 4 new tyres on, and bingo the problem went away. Better smoother exceleration also.
Was suggested to me by SOB that it could be the tyres... cheers mate