I found a review for the Dumb Waiter. There may still be some tickets for the Globe this weekend.

Much of The Dumb Waiter’s detail is of its time, as Pinter carefully layers up the minutiae of observation to create a picture of the crepuscular existence these two lead. The gas stove, lighting the kettle, an Eccles cake, even the dumb waiter itself, all belong in the era. So much so, that to try and present it otherwise without some sort of radical rewrite would be quite perverse.

Not at all sure this is true. The Eccles cake is still widely available I think. Investigations in Ambleside continue.