As I see it almost a third of non supermarket stations are independent or franchise under BP, Shell etc. Yes they can price at will but still need to be seen as competitive as the corporate stations, though catchment area can play a part as well.
That being said the margin between wholesale and forecourt prices is usually very little, some 3-5p per ltr. Each forecourt being it's own cost centre needs to make a profit and most of this comes from the sandwiches and sweets we love to nibble when filling up.
The revenue from what is in the tanks needs to cover the next wholesale delivery. Consider an unleaded tank serving a group of pumps holds approx 22000 ltrs. Change in wholesale costs is potentially going to wipe out any margin the forecourt is currently generating. The more you are going to need to replenish the greater the additional cost and the greater pressure on margin, therefore the desire is to cover costs from what you have left. Hence variations seen from the 'same' branded fuel stations.
I think in these times with the oxygen thief Putin up to his antics most people are pragmatic about costs going up, for now.
That all being said there are always independents taking advantage. War is good for business...
