layshaft - why no oil seal

I am rebuilding the gearbox. I can see on the parts diagram that there is an oil seal at the front of the gearbox for the primary pinion (571059). So i was expecting to see an oil seal on the layshaft too. But there is nothing on the parts diagram. I can't see why oil won't pour out onto the clutch.

The front housing and its gasket keep the oil in box, input sticks out of housing so has a seal.

good point. that makes sense. thanks

I managed to snap mine (layshaft), years ago, not fun

I also did for one years ago, the 2/2a being multi part is not as strong as the series 3 one piece shaft.