Well, 'tis done - and with thanks to John and Mike for the pointers.
An overnight PlusGas soak of the intermediate bearing housing saw the bearing exit its housing on the second whack with a club hammer and drift. Good bit of sticky goo in the housing, cleaned out with solvent and a scotchbrite pad.
Fitting the new RH then LH shafts was straightforward (but slow work), and nice to find SKF have adopted 36mm nuts for the shaft ends, rather than the quaint 35mm originals.
Removing the OE 35mm nuts was interesting: LH one proved impossible (bent bar, etc), and so it was sliced with an angle grinder and 1mm disc. The RH one came off in less than 5 seconds with the air wrench.
Did find removing the lower engine mount/stabiliser tie-bar gave decent access to the bearing holder. The vertical bolt on the tie strangely needed some Whitworth sockets

.
Knocking the new diff deals into place was initially fiddly (no room to swing a small hammer, and angle all wrong), but made easy by using a long length of wooden dowel, pushed through the hub centre, and aimed squarely at the edges of the seal.
So . . . cornering now without clonks, and a much quieter and less backlashy front end. Fresh Total Gear-8 in the box, but unable to find a tube of Forté Gear & Diff Treatment locally, to quieten the 5th gear whine (only at 110-120km/h) - which was there before, and has re-appeared. An Amazon order done.
No way to spend New Year's Day, and Sunday 2nd, but needs must.
She needs to be in decent nick for an ITV/MoT re-test (failed on a split front wheel gaiter), and a small trip in the diary for 2 March, when all of us - lock, stock and barrel - drive to the UK as part of a permanent house move.