the RAF in UK in '49, things were only slowly getting underway in the mid-'50s and although I vaguely remember dining-in and guest nights of the period, think that the old tradition of "never letting the decanter touch the table" had gone by the board: in fact the practice was to slide the decanter along the table
If Danny's memory is holding up well, this would suggest that the tradition of never letting the decanter touch the table was in fact older than has been suggested - could it pre-date WWII?