If you like real-life medical drama, you will enjoy "More Blood, More Sweat and More Tea" by Tom Reynolds, a paramedic in London.
Gripping, funny and heartbreakingly sad in equal measure, I loved every page.
Another freebie is City-Lit: London, where 60 writers describe a part of "their" London. I haven't read this one yet, but it is on my to-read list.
Both can be downloaded free here.
Tom Reynolds' first book is also available for free download here.