[Grubby]

You need to remove the upright and half shaft. I can send you a pdf of that part of the Jag manual. If you have never torn into a Jag rear it is a pretty big job.

I suggest finding a way to get the grease fitting out. You could put a lot of time in the effort and still be ahead of the game.

Alternatively, you could run it until you have a U joint issue. Because you will essentially have to tear down far enough to replace a U joint. That seem pointless to tear down that far to save a U joint. It could run for years without greasing.

John