It's cheap enough to gut the cat, so it's not worth buying the cutting discs and getting my angle grinder out.
Matt from Fusion Fabrications will cut it open, remove the cat, and then neatly TiG weld it back up for just £60, I collect it tomorrow. All the evidence suggests it's holding Monty back, but let's see how much of a restriction the cat really is?
For good measure, I'm fitting a round body straight through silencer on the back of the gutted cat, the new hidden side pipe setup is 2.5" all the way from manifold collector, to tailpipe. No cat, no long tail pipe, and just a "shorty" free flowing 2.5" bore pipe of unrestrictive goodness.
That lot will completely eliminate any question marks over a potential power sapping exhaust restriction