Ian,
Ribble got it from Hemelite (Hemel Hempstead Lightweight Concrete Co.) who bought it from BR to serve their trains on the Nickey Line (Hemel Hempstead - Harpenden), even then it was probably a bit of a leap of faith to buy a catastrophically unreliable type 1. In later years a pair of 204hp Drewry 04s did well enough...
Steph