The pub history site now covers all of London and the home counties around London.
Many of the very early beer houses were actually businesses such as a blacksmiths, and to many of these businesses, the revenue from selling beer was in addition to their normal trade revenues.
In more modern times, many of these beer houses became the modern pub as we know it today, with a far wider range of drinks; others closed or remained as an off-license.
Some of the later trade directories, e.g. from about 1937, are also very useful sources, as they start for the first time ever to name these beer houses as pubs.
There are a number of online sources - e.g. the historical directories site at Leicester University is pretty amazing.
Petty Sessions Victuallers records.
Many record offices hold the victuallers records from the petty sessions for their specific local area. The petty sessions are the court records in a hand-written bound volume, and name the licensee or beer retailer, plus the actual name of an establishment. The downside to these court records are the fact you need to visit a record office to view them, as they are rarely online, and this presumes they actually still exist.
Many publicans became bankrupt. I am sure you will find many cases in question where a publican either 'tries' the pub trade for a year or two, or in other instances just makes too larger an investment and ends up bankrupt, and there are obviously those whom are on the darker side of publican life, i.e the crooks. There is an excellent site which lists the bankrupts in society, and these are listed in the London Gazette. The London Gazette also lists a whole lot more interesting detail, particularly relating to military records.
Another good place to look for pub names and publicans etc is obviously at the Old Bailey online.. I say this is is obviously a good place to search, as many crimes were perpetrated in and around the London pubs, and I am not denigrating the publicans themselves! I am sure there was the odd dodgy publican, but this is London history.
Wills & document sales.
Sale of the freehold of the Wheatsheaf, Duke Street, Chelmsford - in July 1849
Kindly provided by Colleen
A great source for any research is if you can find a relevant will for a person, "I leave my estate to my wife, and sons, daughters etc...". The other official documents are the sale of items, either the relevant building, or its contents.