So I changed my refresh rate in the normal windows display settings to 120 and then set the fps to lock to 60 in Nvidia, set vsync to fast.
Max FPS I then got was 30 in the game (as though it was for some reason halving the 60 FPS I had set in Nvidia?
Regardless, Heathrow (No traffic) in ultra was smooth as butter.
But I must have set something wrong as it was definitely locked to 30