@scrapplecakes:
Unrelated but: common misconception about "Bow's Bells"... a true cockney is said to be born within hearing distance of "Bow bells" and refers to St Mary le Bow on Cheapside in the City, not the area of Bow in East London. Most people in this category in the 20th Century would have been born in St Bartholomews Hospital (Barts). Nowadays however there are very few residents in that part of the City.

At the point that the phrase probably came into use. Bow in East London would have been a villiage outside the "town" of London, let alone the City.