I went once a few years ago, it sold really classy cards, plus maybe wrapping paper, small gifts (?) and that sort of thing. It wasn’t paper chase, it wasn’t a modern type shop, it was the sort of place that people would go back to again and again.
(I have a feeling it was in one of the London Squares, like Trafalgar Square, but I’m hesitant to include that in case it isn’t.)
They might also have their own range of cards named after the shop, or the other way round?
Does this ring a bell with anyone?