Michael Topping, international man of mystery

Something I found this summer in a catalogue sitting in the basement of the Art Gallery of Ontario: a portrait of one “Michael Topping, Esq.” by John Smart. The AGO has at least one other piece by Smart, but I’ve never heard of this “Michael Topping” guy before, and neither has my cousin’s wife, who maintains our family tree—but then, my family tree doesn’t even go back that far: the earliest Topping we’ve got was Robert Topping, my great-great-great-grandfather, born in 1833, who became a boiler maker. He lived at 234 Berkeley, Glasgow, Lanarkshire, Scotland, which nowadays looks something like this. [UPDATE, 2:35 p.m.: Thanks to Quin Parker for pointing out that this is a more accurate Google Street View of 234 Berkeley. Adds Parker: “To me, that tenement looks unsullied by 110 years of Glasgow grime (compare others on street). So old 234 [was] prolly knocked down”]