Linda ,
I had a bad drip on my shower ,today i rectified this without changing the washers .
First step was taking the handle off [prising the Gainsbourough logo off] and then unscrewing the screw.
Next stage was unscrewing the body off by a spanner on the nut on main body the whole unit then comes away just make a note of how its assembled .I just cleaned all the o rings and removed the scale from within the body coated all the o rings with vaseline and then replaced everything .Shower working fine no drips whatsoever.Hope this helps.
John, July 2008