Thomas D. T. Sparrow (c1823- ), bicycle maker and agent for the Coventry Machinists Co and the firm of Sparrow and Spencer, manufacturers of gymnastic apparatus and government contractors for military gymnasia, occupied these premises, known as No. 21A High Road, Knightsbridge for several years in the early and mid-1870s (at which time they also had a shop in Piccadilly).
1861 Living at 89 Piccadilly, London: Thomas D. T. Sparrow (age 38 born Clapham), a Brushmaker and Warehouseman employing 7 hands. With his wife Leah (age 36 born Nottingham). Two servants. 
1871 Patent. '1819. To Thomas Dutton Templer Sparrow, of Piccadilly, in the county of Middlesex, Brush and Bicycle Manufacturer, for the invention of "improvements in darning or mending socks, stockings, or other articles, and in apparatus to be employed therein."'
1872 Patent. '723. To Thomas Dutton Templer Sparrow, of Piccadilly, in the county of Middlesex, Contractor, and Charles Green Spencer, of Piccadilly, in the said county, Contractor, for the invention of "a new or improved boomerang, and mechanical apparatus for propelling or projecting the same."'
1875 Partnership dissolved. '...the Partnership heretofore subsisting between the undersigned, Thomas Dutton Templer Sparrow and Charles Green Spencer, carrying on business as Manufacturers of Gymnastic Apparatus, at 89, Piccadilly, and Dungannom Cottage, Knightsbridge, both in the county of Middlesex, under the style or firm of Sparrow and Spencer, has this day been dissolved. All debts due to and owing by the said partnership will be received and paid by the said Thomas Dutton Templer Sparrow...'
1878 Patent. '3521. To Thomas Button Templer Sparrow, of Piccadilly, in the county of Middlesex, Bicycle Maker, for the invention of "improvements in velocipedes."'
1881. Living at 1 Half Mount, St. Geo. Han. Sq., London: Thomas D. T. Sparrow (age 58 born Clapham), a Brush Maker. With his wife Leah (age 56 born Basford, Notts.). Also two lodgers and two servants. 
Sources of Information
- 1861 Census
-  Gazette Issue 23763 published on the 4 August 1871. Page 13 of 44
-  Gazette Issue 23842 published on the 22 March 1872. Page 56 of 84
-  Gazette Issue 24241 published on the 31 August 1875. Page 22 of 42
-  Gazette Issue 24628 published on the 27 September 1878. Page 20 of 50
- 1881 Census