Should our Car be ULEZ Compliant?

[noTAGlove]

I live less than one mile from the ULEZ boundary. We sold our non compliant diesel estate recently and replaced it with an EV.

However, we also have a little petrol run around (Vauxhall Agila) that has been in the family for over 20 years, and is useful for all the crap jobs that you don’t want to do in a new car, like hauling garden waste to the local refuse centre etc.

I checked the reg (X256 GBP) and it is not UKEZ compliant, as it is not Euro 4.

But then I did some digging and the X10XE engine associated with this car is Euro 2 (not ULEZ compliant), but our car has the upgraded Z10XE engine, and this is clearly stated on the documentation we have (see picture below).

The Z10XE engine is Euro 4, so should be ULEZ compliant.

Have I missed something here? If not, how should so approach this