Try some in Devon on the way in, Bev and Jerry. Cornwall hasn't got a monopoly.As to where to find them...everwhere. Except chemists and clothes shops. My principle when touring in Cornwall is to live on pasties, because you need to taste as many as possible, because I, like everyone else, am always searching for the perfect pasty.
   The first place for a cornish pasty for the traveller is the van in the layby at the bottom of the hill on the A30, shortly after the Cornish border. You can't miss it, you turn in left at the bottom of the steep hill, there is a bit of the old road with public toilets and an oggie-van. And the old bridge to lean over and look at fish and dragoflies while you eating the food of the gods.