The Rose & Crown, London
There's another completely different pub in the book The Forgotten Son with the same name. As cool as it would be for them to be the same (since both deal with GI) it's almost entirely impossible as that pub is in Bledoe, far outside of London.
Talk about it here.
The Rose & Crown, London was a London inn run by Bob Chilcott in the late 19th century.
Clara Oswald worked as a barmaid at the Rose & Crown before assuming the name "Miss Montague" and becoming a governess.
She returned briefly as a favour to Bob when he was short-handed in December 1892. It was in front of the Rose & Crown's back door that Clara met the Eleventh Doctor on the night of 23 December 1892, and the pair inspected one of the Great Intelligence's snowmen. (TV: The Snowmen)