So after the oil leak on the Yam I decided that the gear change shaft must be worn sufficiently to cause the leak, and hence needed to be changed.
In order to remove the shaft, you need to remove the clutch basket in order to draw the shaft out from teh right hand side of the bike. In order I drained the gearbox oil, drained the water, removed the clutch engine cover, remove the clutch pressure plate then all the friction plates and steel plates and finally the inner basket and the out basket, tehn you can simply pull on the gear shaft and it comes all the awy through. I tool a couple of photos, but you can't really see the wear on the shaft, however you can certainly feel it, so it definately needs changing. I just need to hope my parts arrive before Thursday, as we will be leaving for Croix-en-Ternois for the last race weekend of the year on the Thursday evening.