This image from the Morris catalogue for the 1925 season advertises the 14/28 Oxford Cabriolet for the princely sum of £365. With these "bullnose" and "flatnose" cars, Herbert Morris brought motoring to the British masses as did Henry Ford with his "Model T" and "Model A" in the USA. Visit the informative http://www.bullnose.org.uk/ website. Caroline's registration URA 1 (you're a one) is something of a comedy catchphrase.
Caroline appeared in "Stepney the Bluebell Engine" (1963).