Fluid under transmission and clutch making a squeal

Hi, I have a 2.8TD 99 Patrol.

I'm starting to have a few little niggly problems at the moment with the patrol.
The clutch is starting to make a squeaky noise when pushed in. I just went under the patrol to see what the problem is and spray some WD40 to see if that might help. (Didn't seem to.)
I noticed some fluid coming from somewhere underneath. It's under the transmission and over the oil sump.
I have attached some photos to show.

Just wondering if someone may be able to help me workout what may be wrong.

Thanks

Looks like the rear main seal has gone.

Thanks Mudski. Do you think this would be an expensive fix?

Yeah wont be cheap mate. Its a gearbox out job. Might aswell replace the clutch while your at it.
To give you an idea on $$$. I recently paid a shop to remove and refit the gearbox for a clutch. They ended up doing the rear main and a few other things and it was $1350, and I paid for the clutch already.

Oh rite. That's not good. I didn't think leaking fluid was going to be a cheap fix. I guess around the 300,000 km mark things are going to be wearing.
Thanks very much for your reply.

same issue, have a mate mech. we are going to give it a go, is the clutch change needed all the time or just for the covenience that its all off?
i suppose its like doing the timing belt when doing your water pump..