I thought I would check the level of the gear box oil, and why not. According to the manuals, my late B should have a filler on the side of the box. You check the oil by looking at the level through the filler hole. Well, I don't have a side filler, instead there is a dipstick on the top which is accessible from behind the radio console. This is all a bit puzzling. Was the original gearbox replaced with an earlier model? Who knows, and the only way to find out is to locate the number on the top of the gear box (which realistically can only be done by taking the whole thing out). So I won't worry about it.
The oil level was a little on the low side, so I went ahead and drained and replaced the oil with some fresh Castrol GTX 20W50.