I've no idea, but my logic is that if you're driving less than you'd do for your work commute, it'd be unfair to say it isn't local! Presuming your commute isn't ridiculous of course. Me and my missus drove 25 mins the other day for a walk, and I didn't feel guilty about it personally. It was still very much the north west and I could literally see the city centre buildings still when we were up a hill.
I figure that if we were all lumped in as one as Greater Manchester in the tier system, then I can travel within the wider greater Manchester area to partake in exercise.