London Overseer Returns of Electors 1863-1894 - ancestry
 

http://search.ancestry.co.uk/search/db.aspx?dbid=2464

I haven't come across these before, but they seem to be registrations of people eligible to vote. Some are copies of a previous electoral register with amendments and updates written in, so they may help to pinpoint when somebody died or moved away from a particular address, for instance.

Searchable by street address as well as name - the ones I've looked at so far appear to have been indexed by actual people, not by OCR software, so should work better than searching the London electoral registers by street address.

Mostly seems to be North London / Middlesex from the records I have looked at so far.