working class hero An MPV certainly doesn't take 3 times the road space.....
An MPV categorically can take up to 3 x more road space than a 2 seater.
working class hero A Galaxy driven carefully can achieve up to 46 mpg between Tilehurst and the stadium. MAny 2 seaters struggle to get even half that....
On such a short journey fuel consumption figures are going to be pretty meaningless though. And you'd need to specify what sort of 2 seater you mean - are you talking a Ferrari or a Smart car. One will be much worse, the other much better than your Galaxy.