Just put an order for a colour edition and during the process, the salesman mentioned things you can do with the infotainment system. One of them was real-time car info like g-forces and throttle position etc... I thought great! Now, I think I've been told porkies as is this not limited to smart gate enabled vehicles? Is this an optional extra?

Don't think you can access that info through the standard system. Certainly not on mine.

He's possibly been confused between smartlink, which is standard and allows for CarPlay and android auto, and the optional smartgate.

 AFIK, with smart gate option installed  your mobile  connected smartphone, Skoda MFA Pro app can display extensive information of your car.