Left me with the rear casing, fitting the various seals and oil pump. Turned out that the old O-ring that came out was rather skinny compared to the new one. Explains why there was a small oil leak through the selector shafts hole. But that should be well and truly solved now with the double seal.
But before fitting the rear casing to the gear boxes centre plate it seemed like a good idea to trial fit it, just to be sure. Glad I did it as it turned out that the drive shaft supplied with the new oil pump was incorrect (to long), as a result of which the rear casing just wouldn't fit properly. Luckily the old one that came out was in perfect condition so that was re-used. And with the correct drive shaft in place the rear casing slipped on as it should.
And with the speedo drive gear, rear bearing, oil seal and flange fitted the box now is nearly ready to be fitted to the car. But as it stands now that will have to wait till after my holiday and the International Auto Ecosse.