RHeinze: Thanks guys; I've contacted support. And yes, there is a 32 Bit version. As I mentioned, I have the game on Steam and reinstalled recently, works perfectly fine and gives me the build as 32 Bit Windows in the game menu. I also found forum posts on the developers' website talking about the same problem; they answered that normally, the game (on Steam) should install automatically as the locally compatible version.
That's interesting, so is this game a case of needing 64 bit to function correctly and 32 bit runs with reduced functionality making that the reason its unsupported?
I would imagine a game with this level of simulation needs a lot of ram.
Did support say if they were going to supply the 32 bit version?