I use Pennine Lubricants (I think they are in Sheffield) for all the oils I ever need to use (tractor oils, hydraulic oils, chainsaw oils, two stroke oils, motorbike oils).
That green stuff from Halfords is good if you want to find out where seepage is coming from.
I use a Morris brake fluid oil for my JCB. I have also used their Running-in oil for my M20 and a rebuilt Leyland 270.
Regards
Pat
ps If oil seeps out of the Primary Chaincase, then a) you know it had some in and b) constant topping up keeps it fresh.
