Ok, massive long shot but I lost a ring this evening (Thursday 14th) somewhere between the Crypt cafe and the Savoy theatre.
It's not valuable but it's sentimentally precious and I would be forever grateful to have it back - so thought I'd try and harness the power of MN.
It's a textured silver spinner ring, similar to photo but more texture in mine.
I checked around me in theatre and will speak to both them and the cafe in the morning but on the tiny off chance one of you lovely lot was in London and happened to pick it up...