Gearbox leak advice

When I had my car up on my mate’s ramps I was quickly able to spot two areas of oil contamination. Now the previous owner warned me that the cam angle sensor O-ring was leaking so the oil down the back of the engine was no surprise. But the rear of the gearbox is also heavily contaminated with oil so I’m assuming I have a second leak.

I plan to get the clutch changed anyway so that will be a perfect opportunity to get any gearbox oil leaks fixed. To avoid any unnecessary delays I want to supply all the likely parts so the job can be done quickly. To that end are there common seals on a '91 Roadster gearbox that are likely to be suspect and which I could get replacements for?

Of course this is all unless someone can tell me that a leaking CAS oil seal would result in oil all over the gearbox? I can see how in theory it might be possible but I wouldn’t like to assume that’s the cause.

Any and all advice warmly appreciated.

 CAS “O” ring leak will contaminate bell housing area of gearbox, but the leak at the rear is probably the rear seal where the propshaft exits the gearbox. Simple to change, especially if you are having the box out. If not it is a case of removing the prop shaft, lever the pld seal out and tap a new one in. A suitable sized socket or piece of tube helps.

Possibly this but check for your car. :-

Thanks Phil. Doesn’t look too expensive so will order and it can be swapped out irrespective, not gonna hurt to have a new one in place. Hopefully it will also solve the leak.