I believe the ejection seats and oxygen generation systems are optional on the G120TP, so no redesign will be needed, as the baseline design does not include them anyway.
Another thing the UK G120TPs do not appear to have is an autopilot, which, along with the lack of oxygen generation system, rules out downloading some of the high-level nav elements of the multi-engine cse to the G120TP.
The lack of bang seats also means we won't likely see the G120TP being used for some elements of the BFJT course, i.e. low level nav.
One question is, given the large increase in RPAS pilots the RAF will be needing due to Protector, will the G120TP be used to provide EFT to RPAS pilots, or will that continue as a separate cse on the Tutor (or be scrapped altogether once the RAF gains full control of it's RPAS training pipeline)?