Cheers for that Mark, you learn something everyday
It was only after posting that I then found the 3dr rally car thread on here too with the Jag diff in. Didn't know the history behind it!
I amazed the drive shafts lasted though - it was definitely something I wanted to tackle from the outset, but at least I'm where I prefer to be on the over engineered side of things! That's where Rod came in, as I used the same company that did his and a set for James IIRC.
Seeing all the supra stuff makes me wonder if I could have achieved something similar a bit cheaper, but there will always be something new coming along, and sometimes you just have to crack on and get it done.
Cheers
Iain