It is Ford's own country, the carmaker employs thousands in the region, so it's hardly surprising that Thames outperforms national sales. The surprise though is the appearance of BMW in the top 10.
BMW GB is based in Bracknell, Berkshire, and there are a disproportionate number of business headquarters in the Thames region, many with BMW-driving executives.
These two factors probably account for BMW holding 4% of new and used car sales, and also 4% of the total VIO. Nationally BMW does not figure in any of the top 10s. BMW used vehicle transactions are significant in all but one age group (years 0-1; probably distorted by other manufacturers' preregistration activity).
In the 4-5 year-old range BMW achieves 5% of transactions, making it the sixth most popular brand in this age band. VW also performs better than it does nationally in all categories.
Fiat Punto appears to perform particularly well in the Thames region where it is ranked third out of all models (table 7). A high proportion of these Puntos appear to be sold on in their first year of registration, possibly explained by dealers registering them and selling them on as used cars, although the period analysed was also run-out for the old Punto.
Conversely, Golf and Focus achieve a high new car share without the high volume in year one used car transactions. This may reflect the age of these models (Focus was launched in the analysis period) but is more fully explained by genuine retail demand.
The Golf in particular doesn't show up as a common model in used transactions until the 2-3 year-old range. The Golf is also ranked higher in every age group in Thames than it is nationally, according to the VIO data.
Focusing on dealer activity, Ford franchises perform considerably better than the national average - new car sales averaged 999 per Thames Valley dealer against 550 nationally.
Again reflecting the affluence of the region, used car sales are lower per head, averaging 107.9 per 1,000 population against 115.3 nationally.