One if mine was leaking (on the LHS half shaft). I bought the part from mx5parts and had a friend-of-a-friend who is a mechanic fit it, he charged me £20 and it took him half hour.
I think it is an easy job, I was just worried about the bolts on the half shaft being a pig, I bet they’re fun to undo lying on your back on a driveway!
If you have a pit it could be easy. You need to undo the upper wishbone on the suspension to get enough room to swing the half shaft out of the way. The splined output shaft then pulls out the diff, it is tight as it has a sprung clip on the end. More guidance here:
Oh well. It seemed I was lucky having the bolted half shafts, is it something to do with the vlsd? From what I know the non-lsd cars still have bolts, they just have different looking connections (the vlsd ones have ‘wings’ on). I thought all mk1’s had bolted half shafts/output shafts?
-best of luck with the oil seals whatever happens, let us all know how you get on.