Don't think that's possible???
How you they prove you removed it if you haven't had the car from new?
If the physical presence of a cat is not checked at an MOT then how would it stand up in court? It's perfectly possible for the car to pass it's emissions test without a cat installed.
I don't know mate to be honest.
Probably the same way that an old car of mine passed the MOT with tinted windows, yet I got pulled in for a VOSA check and got done for it.