Colin,
The early rounds will be regional but that still means pretty much anywhere in Scotland. By the later stages (semi finals, possibly quarters) it could be further afield. Last year's winner lives in Essex but also plays at NBWL. We try to make it as practicable as possible but inevitably, with a national competition you could, if you get to the later stages, have to play opponents from the other end of the country, though I'd expect neutral (and interesting) venues to be agreed for a match where the participants were a long distance apart.