Yes, just as you say, Cavo, Rover 75 V8 Tourers are a bit "hen's teeth" ! Even worse if you fancy a LHD one (3).
All Rovers are automatic, incidenly, and only a handful of ZT 260's are automatic. 7 or so in Australia I believe, and a couple of prototypes for the Rover V8, badged as MG ZT 260, in the UK. There is also a LHD ZT-T 260 Auto (only one?), owned by member 'scoubix' in France, but I'm pretty sure he wouldn't be separated from it.
Do you have some photos of your ZT-T 260 #578, Cavo?
We don't have one even in the Forum 'Photographs-of-Cars-Ordered-by-VIN' thread I see.
David