A cluster of tiny artworks near Covent Gardens

Near Covent Garden, a newish development of shops on Mercers Walk has recently added a cluster of tiny artworks that provide a bit of a treasure hunt to seek out.
They’re in walls and the floors, and are all related to a City of London livery company, the Mercers, who happen to own most of the land around this part of town.
Most of them are quite easy to spot, and others are in plain sight, but on several visits, I never saw anyone looking at them. They’re possibly a bit too small an