Very good Stinky Pete. HRD 1924-1950 was founded by Howard R Davis and built Massey designed machines of advanced design. They had 349cc and 190cc sv and mainly ohv JAP engines, a low saddle and very sporting appearance. HRD himself wone the 1925 senior TT and Freddy Dixon the 1927 junior TTon these machines. Sold to OK Supreme in 1928 and again to Phil Vincent of Vincent-HRD fame.
Info courtesy of Erwin Tragatsch "The Illustrated Encyclopedia of Motorcycles"
Over to you Pete,
Phil