It is so tempting to arrange the family of "old-school" Bentleys in ascending order of engine size that it comes as quite a shock to realise that the "6 1/2" is several years senior to the "4 1/2". It came out in 1925, although the now better-known Speed Six did not appear until 1930, and Le Mans, that famous Bentley advertising medium, did not see a six-cylinder model until the same year.   Continued...