Woman with Ford Cortina in the early 1970s

A picture of a woman leaning against what I believe is a Mark II Ford Cortina which is parked outside some rather impressive looking houses. The car registration letter is G which is 1968, and her clothes suggest a this picture was probably taken in the early 1970s; I remember my Dad had a similar coat around that time.

The location is unknown. In the series of negatives this picture came from there are locations in London and what appears to be South Africa, but the registration of the car suggests this is definitely in the UK.