Right now there is an interesting weight on offer at ebay:http://cgi.ebay.ch/ws/eBayISAPI.dll?ViewItem&rd=1&item=180208515841
It contains a 1980 Whitefriars (monk) cane. To my knowledge Caithness bought the Whitefriars name in 1981, at least the first "Whitefriars" weights in the Charlton catalogue are dated 1981.
But then there were quite a few other paperweights produced during the early 1980ies, with the dated monk cane, not mentioned in the Charlton catalogue, including the "mini butterfly" described by Allan Scott somewhere else: these weights were (at first) produced at John Deacons' studio on behalf of Caithness (who didn't have the capacity at the time to do it themselves). These weights started in 1982.
What puzzles me: the above 1980 paperweight is using exactly the same white/pink canes made by Harry McKay for the "mini butterfly". Does that imply that already in 1980 Deacons/Caithness produced "Whitefriars" paperweights - or did they inherit some old dated monk canes and used them later - or ... ?