That is correct Jim. According to my man anyway, and he usually knows what he is on about. He was a fitter/driver with Hudsons in the early 1970,s. He said that when it first arrived at Hudsons ,it had a wooden cab. 
Then it got the Leyland one fitted. It has been retired for a number of years. He started to tell me how many sprockets it had on the flywheel; I think he must have stopped when he realised that I had fallen asleep. 