It's not all of the faces, but it's a pretty good spread.
On the buildings of the victorian Cricklewood, on the building pillars - between each shop front - there is a ornate 'top' facade - usually corinthian or doric columns, these are topped by a face.
These are drawn from a gothic almost rustic tradition and involve leaves and flowing water swirls.
Many of them appear to draw on the 'greene man' tradition of olde england.
Carvings of the Greene Man are known in architecture as foliate heads or foliate masks, some are naturalistic but in this instance they are just decorative. http://en.wikipedia.org/wiki/Green_man
Traditionally the simplest show a man's face peering out of dense foliage (they are usually of a man and rarely of a woman).
Some have leaves for hair, often with a leafy beard.
In this instance in North London we have the development of a whole family - very young, old and indeed including a women - it is a further exploration of the idea that this might be the depiction of a family of the architect, builder...
This part of London (Cricklewood) build up very quickly following the arrival of the railway in 1868 - from 1880 the building locally went up apace and so it is to this era that these carvng belong. Perhaps it is the family - I suspect we will never know.
One thing it does confirm for me however, was the extent to which two or three maybe six or seven building firms dominated the massive growth of building here in north west london. There are three really distinct building styles - that employed in Belsize and Hampstead, that of Swiss Cottage and South Hampstead and this of West Hampstead and Cricklewood.
This part of north west london certainly saw massive growth with the advent of the railway and the need for mass accommodation - it certainly did seem obvious that it might be so personalised...