Did I imagine some 50% off (or 2:1) deal if you showed them an Oyster?

Has it lapsed, can't find any mention of it today.

Last autumn, I think. Certainly not available in Feb.

Maybe next autumn? It's very expensive at full price.

Yes it is. Don't pay £13 to queue and stand in a pod, instead have a glass
of champagne at Vertigo on the top floor of Tower 42 for £9.50. The view is
better, its cheaper and you get a glass of champagne.
http://www.vertigo42.co.uk/