If you can do with the truck for a few days Id get your rebuilt.

I had my 90 one rebuilt a year years ago by a hydraulics company local to me
(found in Yell and called up). He rebuilt and double sealed it for about the
same price (maybe cheaper actually) than getting a swapped one and I know
the works been done old'skool

Tim

Probably not much help, but I replaced one a couple of weeks ago for a
customer, he sourced the box himself so I don't know where he got it from.
Might have been Ashcrofts?
What I can tell you is this:- If it's a TD5, you need it up on ramps, end of
story. Lower coolant pipes have to be removed from around the bottom of the
crank pulley/thermostat area, involving a complete drain-down of the cooling
system. The ACE system, if fitted, needs the right-hand side link unbolting
to allow movement of the ACE ram and arm, as it fouls access to the 4 bolts
holding the box to the chassis. Make sure it comes apart in the
straight-ahead position as you must not turn the column with the collapsible
steering link removed (according to landrover). Oh, and get a new drop-arm
as well, it's so much easier than even trying to get the old one off the old
box!
Badger.