@PupFlyer, it may be worth contacting various FAA CFIs and seeing if they have access to a suitable aircraft. I have used Brian Hamilton at Thruxton for BFRs and he has a twin Barron which could be used to get a complex / high performance sign off (I’m guessing that when using a MEP with two engines would count as a SEP sign off for the reasons you need). He may well have access to a suitable SEP too.
I can PM you his contact details, if needed.
Iceman
You are still dangerous! You can be my wingman
anytime.