Had a call from Martin Percy last night to say mag for Marconi-Stanley engine is finally ready (I took it up to him on the weekend of the Lamport rally, but you can't rush a good job!). Martin was able to tell me that this model was introduced in 1923 and that it clearly did not prove very popular as he has never seen one before (he also observed that it had a rather poor magnetic circuit). This is the first real clue we have had as to when these engines were built.