As you can see its a Ford part, the laser engraving reads.
Ford 4S71 - 5E212 - EA 1426166 T2A 1A 24K073
The part numbers confirm the cat is from a Mk3 Mondeo 2.0 Duratec, Ford quoted this model as making 145hp. The Ford cat's estimated internal envelope is around 76% greater in frontal area than my small sports cat, it also has 15% more volume so it is looking highly likey the sports cat is too small to support the kind of power levels Monty's engine has been built to deliver.
The Ford cat chosen by Morgan is actually a quality thing with a proper ceramic core, it's way better than the silly little so called sports cat with its cheaper metal core. I did originally specify it, but I now think that was a mistake, for starters it was really too small to support much over 180hp.
Once the de-cat has proved itself, I'll have Matt at Fusion Fabrication make me a new cat pipe for MoT time, and using the 15% larger Ford cat with its 76% greater frontal area!