Jaguar X300/XJR Differentials - Anyone familiar with these?

[Cluffy]

Afternoon all,

After speaking with @grogee and @Schaefft this morning at Rustival, I have even more motivation to get on with the Moon Mile XJR. 

The diff has been leaking - for who knows how long... Google has provided me with some useful and some scary information as always... A few people suggesting the breather gets blocked, pushing up pressure inside making it leak by the seals.. Truth in this..?

The whole rear axle is out, so looking for advice on anything... Even just the easiest way to get the diff out, or obviously how to break it open and swap out seals etc... 

I'm keen to do what I can while it's out without spending more than I bought the car for in getting a full professional tear down and refurbishment. Obviously when it's back in the car I'll drain the old fluid and put in fresh!!