Striped down the back passenger compartment panel, fuel tank & loom today to gain access to the diff. I managed to measure the oil through the breather pipe hole in the top of the housing with a piece of wire. It seemed to be very low on oil, so filled in up as best as possible to the filler plug level. As reassembled and off for a test drive in the sun.
I cannot determine if its resolved the issue, but its certainly going to help.
Heading off from Plymouth to Exeter next weekend for the Kitcar Show. This should be the first real test for my home engineering.
Drove down a farm lane today and got sprayed with cow dung splatter of the front wheel! Wish I had put my helmet on!