National Children's Home.
These appear to be all resident pupils, except the pianist, with sheet music, and a middle-aged man, both presumably on the staff.
Three dulcimers played with hammers, a bass drum, three mandolins, a side drum, a set of tunes bells on the left, a set of tubular bets next to it, a set of hand bells in the front, and a four-tier set of tuned bells on the right.  The children are in school uniform.
The provenance is not known, but English, pre-Great War.
From the Reg Hall Collection.