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.
The pub history site now covers all of England, except parts are still missing!
Blisworth, Braunston ,
Gayton, Long Buckby,
Shutlanger , Stoke Bruerne , Welton , Westbury