Many accurate 1921 census transcriptions have already been added to the pub history site, including London, and parts of Middlesex. If you can contribute to the site, send me some details to Kevan, along with some description of the specific property.
St Giles pub history index
Belton street is renamed to Endell street, but this pub is no longer in existence by 1846
A listing of historical public houses, Taverns, Inns, Beer Houses and Hotels in St Giles in Fields, London. The St Giles in Fields , London listing uses information from census, Trade Directories and History to add licensees, bar staff, Lodgers and Visitors.
Residents at this address
1832/M Shepherdson/../../../Robsons Directory
1833-34/M Shepherson/Three Tuns, 35 Belton street, Long acre /../../Pigots Directory
1839/S Willament/../../../Robsons Directory
1840/S Willament/../../../Robsons Directory
1841/S Willament/../../../Post Office Directory
1842/S Willament/../../../Robsons Directory