Thanks for the replies everyone.
The engines I have are fitted with cats as OE. Happy to keep a cat.
I thought the statement that 2002 on cars with different engines adopt the emission standard of the car (not the enigne) would mean the relavent Euro standard, but that appears not to be the case?
If it’s the default Petrol spec for 2002 on, as in the book, I have no worries with either.