So, by way of an update.
I'm getting more used to the details in the Delta now, and am looking to explore extra sensors.
I had considered that having a map sensor may put me in a position to improve the tune of the bike. I reached out to SCS regarding their thoughts on what additional sensors may be a good way forwards for better tuning. Interestingly their response was that all the input sensor pinouts of the ECU are used by the bike in its current state. This may offer something by way of explanation as to why Norton went back to OMEX. If they needed a MAP sensor to assist with emissions (for Euro 4?), the additional sensor not being available to be added to the Delta could possibly lead them back to OMEX.
edit: I have been assured it wasn't that by someone who definitely knows.....
Having said that, I note that there appears to be some capability in the ECU to assign pinouts, so will review if removing the IAC has given me anything available.