I wonder how the economics of supermarket fuel discounts work? I’ve recently had some 5p / litre vouchers from Tescos. I do try to note the expiry dates and make use of them, so it becomes a kind of game to get the maximum benefit (biggest overall discount) at minimum cost (least going out of my way to take advantage of it).
Going to Tesco in Barnstaple to fill up today could be seen as a bit of a detour although, since I was en-route to visit my mum, it was even less out of my way than normal. Job done!