So I've finally found a replacement - a very healthy TD5 Adventurer (thank you, Bill of Fred's Cars) in Wimbledon green. Most of it seems to work and though it's nothing like the spec of the dead ES, it feels more normal. No ACE but stiffer suspension from the commercial so still not too much body roll in corners. I do miss the Harman-Kardon system, though. The basic LR radio cassette is a bit, er, basic. Still, it does have a DVD player set into the ceiling even if it doesn't actually read DVDs (yet)!
The 15P engine feels very good and I'll probably get it remapped. Chassis has a fair bit of surface rust so a good clean and waxoyling will be done before it starts raining again. Let's hope this one holds together!
On the basis of the disaster this thread arose from, I have also ordered voltmeters for this car and my van too. They plug into the cigarette lighter sockets and provide two USB charging ports too. A spot of monitoring - wish I'd had one 3 weeks ago! Just £4 ish each on fleabay.