http://en.wikipedia.org/wiki/Brocklebank_(automobile)

I need a suitable get-away vehicle for the art thief to escape in Book 5, and I think a 1927 Brocklebank may be my car.

Big enough to accommodate all the wedding gifts that disguise the true purpose, it came in two and four door options.

I think it was also rare enough in the UK at the time to be more easily ‘chased’ by the Police (in other words, there are not hundreds on the road, and therefore its not easy to lose in a crowd of traffic).