Gary, that's very interesting. I wonder when that sheet was written at what it actually relates to. And what might "Acc" refer to in that heading?
Data on Chic Young says that, except for his national service period, he was at Moncrieff's from 1946 to 1960, so the info could refer to something over a spread of at least 16 years. If we knew the dates applicable to all those other folk, perhaps something would become apparent.