I have been meaning to do this job on my 90 and as a result of my research I found this thread and also the following information:

https://www.landroverworkshop.com/axles-differentials/pinion-flange-pinion-oil-seals

The link lists what seals go with which drive flanges and mudshields, and what spacers are required.

It seems a good site to me so thought I would share.

Rich

Noticed mine was dribbling a few days ago so ordered up the parts. This guide will be very bloody useful,
Many thanks.