Just two new models came out in February 1957, the Standard Vanguard III (phase 3) in normal and Mechanical form.
These were not a common sight on our roads at the time. It does bear quite a few similarities at first glance to the Vauxhall Velox and others in that range.
This is the Mechanical 207M, always in a creamy yellow colour. Really quite rare now in decent condition.
The normal version, 207, was the first with two-tone paintwork and the colours are a very pale green and bright red. You'll find two versions of this: one with the red coming down to the bottom of the window line and a less common one with just a red roof.
There are minor shades of pale green some appearing more like a pea green perhaps but really this model has very few variations. Most differences will have been the result of sunlight fading the colours or, often, someone trying to freshen up the appearance!