Hiya
Ah a fellow social history enthusiast
The works of Gissing are fictional but are reputed to be reasonably accurate portrayals of everyday working class/lower middle class life, there's a list here:
http://ehlt.flinders.edu.au/english/Gissing/Gissing_HomePage.htm I've read most of them, Nether World is I think a very candid picture of working class life based around Clerkenwell London and most of the references are factual. The Odd Women is an interesting portrayal of working/lower middle class unmarried women, and their options (limited!). New Grub Street is also intresting from the point of view of the lack of mobility between classes (focusing on working vs lower middle generally).
There's also a book (name escapes me, but will look it up if you're interested) of actual autobiographies/diaries of working class people generally in the mid to late Victorian era - if memory serves me correct, things like Miner, Shopkeeper, Hand Loom Weaver, footman are included. It's quite expensive as it's been out of print for ages though. A must read though ... my copy has been lost
Mayhew's work (and books co-authored by his brother I think) as Old Rowley suggested are seminal works of the time and rare sociological investigations/surveys into working class life. London Labour and London Poor is excellent.
Hope that helps, and good luck
Biker
