Yes - the incorrect date is my fault - I was in a hurry and read the year off the J. Knibbs serial number index. It is, of course, a 1919 or 1920 Lightweight model.
Ahem, shame on you Paddy ... Go stand in the corner facing the wall while I go and get Mrs Correctional to give you six of the best, and try not to enjoy it as much this time . ATB: Gareth W-B.