Following my own, somewhat brief, report on the Whistlestop at Waterloo Station, wardytron adds the following photo:
He also says, incorrectly, "Its official address is 'Unit 28, Waterloo Station, London SE1 7LY'". Unit 28, of course, is actually a branch of Monsoon.
He adds, with more accuracy this time, "Twirls were 70p, which is on the high side, but the shop was well air-conditioned and not as busy as the WH Smith I photographed yesterday. Whistlestop operate a 'Meal Deal' system, where you can buy a sandwich, bottle of mineral water and a packet of McCoys for £3.59. There's also the option to exchange the McCoys for a Mars Bar, although sadly not a Twirl. However, prolonged and intensive lobbying might produce a U-turn, who knows?"