After many hours of reading the debates on here and other sites about diff and gear box oil I could'nt come to a specific conclusion.

I decided to go out on a wing and use lucas gear oil 75w 90 for the box and diff. ( ver 4 type r )

The oil seems to be working a treat. The gears are much more fluent and no nasty noises from box or diff.

£60 for both and its even left me 2.5 litres towards the service.

As there isn't much on this oil It would be good to hear any other opinions regarding this oil.