i was told the pricing was dependent on whether it was classed as a city or town location and then it worked off a radius from the centre of that location outwards with a decreasing price structure with the benchmark price being always less than its competitors in the main city/town centre location.
Spoons in edinburgh centre are £2.95 a pint of lager go 3/4 of a mile out of the centre classified as "non city centre" and price drops to £1.99.
basic economics supply and demand i guess