I was recommended this by a friend while on holiday and loved it.
Full set 77p on Kindle
I'd be very surprised if Helen Fielding has not read it - some of the turns of phrase are rather Bridget-Jones-ish.
I'd now really like to read more only-mildly-fictional diary-style books, because I very much enjoyed hearing more about everyday life in the 20s and 30s, and think it a fun way to learn more "history".
Any suggestions?