if it is a mark 1 you first need to remove top half of dash board 3 sccrews along the window and 2 either side just inside door then remove steering wheel casing top and bottom pull top of dash away and you will see 2 screws holding speedo unit remove these then look at bottom of speedo unit where steering casing was 2 more screws these are a bit tricky when these are removed pull speedo unit out firmly but carefully just enough to get hand round the back of it hold speedo cable and give a firm tug to remove flip unit over and you will see bulb holders find out wich one it is the main one is in the middle but another one at side of speedo twist bulb holder and pull to remove and replace then reverse procedure to refit and good luck!!hope this helped
dave paz
September 2009