L&M say this was “on Market Hill, by St Edward’s Passage” and closed in 1790. The map shows an approximate location based on this. It’s possible that this is the same pub.
The overlays that highlight 17th century London features are approximate and derived from Wenceslaus Hollar’s maps:
Open location in Google Maps: 52.204595, 0.118840
"Ex Three Tuns, Castle Street, Cambridge
"On this empty plot once stood the early 17th-century Three Tuns (also known as Whyman's Inn -- a succession of Whymans are listed as publicans throughout the 19th century), reputed to have been a lair of Dick Turpin. It was pulled down in 1936, although judging by the photograph I've seen of it from 1903 I'm amazed it remained standing even that long." http://www.flickr.com/photos/beery_pix/6918285639/
Chart showing the number of references in each month of the diary’s entries.