i have a 1990 Defender 90 200 TDI. I changed the rearoutput seal already. Now it seems that there is the same or more still leaking but just forward of the seal. Is there another seal behind that? I have to change the bearing as that was burnt out and it whines. I figured while I’m back there I can change out the seal that is making it leak after every trip. Hopefully the picture helps.

There is a large gasket there, on the rear of the block. Could also be block to ladder frame and ladder frame to sump, both rtv sealant.
Did you use a branded rear crank seal?
Cheap ones are rubbish.

Bugger, never looked at the pics properly! Can't see them very well on my phone, ignore my post above.