Master Butcher @ Islington, London. Reginald Stearn's family tree does not indicate that he actually lived there, however.
His father, Arthur wholesale butcher's address was 109 Charterhouse Smithfield London, the London Charterhouse being a complex of buildings in central London.
According to one source, Arthur Richard amassed some wealth in supplying meat to the almshouse "London Charterhouse", hence building a large house (Charterhouse Lodge) back in Grantchester, and then a row of cottages in Cambridge also called "Charterhouse."
But, in his notes, Reginald Stearn notes the date of the Lodge renovation as 1880. It's most likely that Arthur's 48 yr. old father had enough money to actually pay for the reconstruction, as opposed to his 25 year old son. An occupant of the Lodge is noted in 1883 Arthur Stearn- it could have indeed been the son. There is no record of the Stearns resident there after 1900.
In his notes, to further complicate the issue, Reginald offers as the possible alternate owner of the Lodge, Arthur Edward Stearn, son of William Holder Stearn, instead of Arthur Richard.