Starter Catalytic Converter on 2002 Boxster 986

[Robert of West Yorks]

Hello, my first visit to the forum as a relatively new owner!

I have an engine warning light for an ageing oxygen sensor pre-catalytic converter on my 2002 Boxster S. I managed to get a parts manual, and checked the car info, and it seems to tell me that the engine is a M96.21 type. However, when I look at the parts manual this engine has a starter catalytic converter. I had the car up on the jack for a peek and I can't see that mine has one. Can anyone shed any light on this? Could it have had a replacement exhaust system without starter cat, and would this even work with the missing sensors etc. associate with it? Or is it more likely my car, despite its serial number has the 96.20 engine (maybe a model crossover)?

The fault code is P1275 $0011 which I believe is the oxygen sensor pre-cat, but I am trying to check if it is pre-cat or pre-starter cat.....

Any hints greatly appreciated before I try do any fixing!
Cheers
Robert