Hi Carl, and welcome to the club.
I take it that there should be another 0 on the mileages.
The 2.7 Gemini Diesel was designed as a joint venture between Ford and Peugeot and the 3.0 Diesel is an uprated version to meet the Euro 6 requirements and is naturally a little quicker than its predecessor -- which is no slouch either, and is the engine that powers the S Type Diesel.
The 2.7 litre Diesel your are looking at is a very low mileage for its year, and I guess that it is in very good condition, too. The 3.0 litre diesel looks to have done a fairly average mileage and should be in a similar condition.
A lot could depend on the mileage you will be doing, as both engines are quite good, but if you are going to do a big mileage you should note that a cam belt change will be needed at 105,000 or 10 years. If you are going to do a low mileage, I would probably go with the later model.
Regards,
Peter.