see Poland Street 19 to 44 in London Addresses dataset
Thomas Maggi Italian warehouseman 32 Poland St SunFire 1782 / the ratepayer at this time was a grocer William Tuff (QV*) / there was a print by Bartolozzi after Biagio Rebecca of Natalis Thomas Maggi, published 20.6.1788, first mentioned in Manson's catalogue of 1788 (as scarce), in Bromley (1793) this Maggi was listed as a musician died London 1787, on the print his birth date was given as 9.3.1735 at Forijulii (modern Friuli, Italy), but I can find no other source on his life. The print showed him holding a book, the name Maggi was common enough in Italy and a number of authors and engravers of that name from sixteenth & seventeenth centuries are in biographical dictionaries. Many musicians lived in Poland St and it wouldn't be strange to find one diversifying into grocery, but the name didn't appear in ads for concerts &c