Prop shaft came off easily enough, just needed a reminder with the lump hammer. No heads rounded off. Marked.

The slide bar cross member, showing the shiny section where the mating faces of the gearbox and prop shaft have been grinding against it.

Having trouble with the macro function on my camera, sorry about the lack of focus.

Gearbox mount offside. Looks alright.

Gearbox mount nearside. Looks alright.

Gearbox nose showing underside and weepage limit.

Gearbox nose from top, showing that leak is not coming from further forward.
Took van for 20 min drive. Still slight ringing sound when high throttle at inappropriate RPM. As before, as everything was hot, there was no crunching sounds.
Went to Halfords to pick up a red bucket for the Crimbo tree. While there, on the off chance asked if they had gearbox filler plugs, as I think I've cross-threaded the rear one, chap replied "No never heard of them, but we've got gearbox oil", me "how does the oil get in?", him "dunno, can't help you". Made me chuckle.
Front diff magnetic drain plug. Looking alright thankfully. (Found it impossible to get an in-focus shot, sorry).

Front diff oil was black, not golden as I stated earlier, got fooled by the thin sheen on my gloves.
Tussled and failed with obstinate slide bars before I could drain rear box, and then ran out of time for today. I'll warm up rearbox and drain it on Friday when I'm next off. I'm not looking forwards to seeing whats on the drain plug! In my layman's eyes I'm thinking the box maybe damaged as its nose is grinding against the crossmember slide bar. Worn out bearings coupled with an oil leak?
Couldnt find part number on engine oil filler pipe. Baz, I maybe giving you a call sometime though!
Getting peed off trying to find decent oil. Halfords none on shelf, but at £9 per litre for Comma SW75W-90 GL4 I'm not to worried. Went to CAF and bought 5 litres of Comma SX75W-90 and then realised it was GL5 not GL4. Queried this with shop staff who said Comma are dropping GL4. So I've got plenty of 75W-90 GL5 for the front diff, but only 0.5l of 75W-90 GL4 for the gearbox. I'll have to source some GL4 in qty before I drain rear box on Friday.