Fitting new oil seals. Differential and Gearbox.

Can anybody offer any advice on the procedure for changing the oil seals at the rear of the gearbox and the front of the differential.  I have been living with slight oil leaks from both of these and this seems to be a good time to do something about them. The differential is the worst at the moment.

I have now done the differential seal and found it to be fairly simple job.  Happy to share the details with anybody who is interested. I think I may live with the gearbox leak(s) for a little longer as access looks rather difficult, and it may even involve removing the gearbox.