Simon, ok so I was misinformed, no Jaguar engine, but it was the Mondeo engine. Thanks.
Bob, the ECU was changed via my Morgan dealer within the period of warranty. It was a MMC measure, no idea who made it for MMC, and also no idea if it is another hardware or just another programming.
The dealer and me thought that all S2 drivers would benefit from the change at this point of time but the offer disappeared quickly and calmly. Only a few cars got the ECU change to my knowledge at my dealers place.
Just a guess, may be Simon can confirm it. Later on I also had the S3 Model, Roadster Sports. The engine was almost identical with S2 but may be (I am not sure) the manifold had a slightly bigger diameter?
But this S3 car had no rev hang and plenty of power, it felt a bit like my S2 after the ECU change but slightly even more so.
May be you could be happy to get a S3 ECU (or that programming) and drive it in the S2? Perhaps easier to order or clearer to explain someone to want a S3 ECU than modifying an existing S2 ECU without any clue? The experts must tell if there are no issues to do so.