The Escort (1998 1.8) won't rev above 4k and has no power. When you release the throttle there's a rattle from underneath, so I suspect the cat has gone.

Could the car pass an MOT without any insides in the cat if I smashed it out?

If not, is it a simple job to replace, and is there a supplier that anyone can recommend to get a replacement?

And is there a px value for the old one if I get a garage to replace it, or should I ask for it back and try to sell it to the scrap yard?