I think that the land inbetween Cricklade and Blunsdon is where they are looking. I've nothing to back that up, it just makes sense. NWBC rather than SBC, most of the land is privatly owned by farmers I'd imagine.
Good transport link with the A419, not far from Swindon itself. I could be wide of the mark but it would all make sense to me.
I live near there some of the time and would say there is no chance of building a stadium there, dunno which side of the road you mean but pretty much all of the land on the right as you go down Blunsdon Hill is owned by one guy and he wouldn't sell, it would never get planning permission anyway as it's all greenfield land and there is a small forest on the right.