Ok, over the years I have either topped up or refilled the gearbox/od. As my garage floor slopes down, I've always set the car up on stands to be level, using the sill treadplate as a spirit level reference point. Today I was doing a routine oil level check and it occurred to me that even if the car is set level, the gearbox mounting is not close to being level. If I set for 'level' using the gbox top face, there is a marked difference between that and the chassis, which makes quite a difference in oil level when topping up, until oil stops running out.
I've never really thought about this before, but which is correct?🤔