Disco 1 Oil leak from front hub, NOT MY D2

Workmate showed me today, oil all over his wheel, appears to be coming from the hub.

It is not the seal and shiny metal bit on the axle, but where there are 5 bolts inside the end of the axle inside the wheel centre.

What does he need to order to fix it and how easy to fix is it?

I am not an expert on the D1 and it looks very different to my D2

Here's some pics... Early and later models.

Early model

Looks like there is a gasket behind the driving member. Worth a try.