1. Croall actually owned H.J.Mulliner & Co.Ltd. from before the the First World War until it was sold to Rolls-Royce in 1960. They did build bodies for each other if deemed neccessary.
2. This is a Drop Head Coupé. Doctor's Coupé was a term used very loosely. Of course few doctors would earn enough money to have a Rolls-Royce with this body, and then would be need to use it to do visits to patients.