The 'Journal of Glaciology' [289] has a 'Report on the Snow Survey of Great Britain for the Season 1949-50'. In that report a new section on snowfall in British coastal waters stated:
'Through the courtesy of the Elder Brethren of Trinity House and with the co-operation of the masters of twenty-six lightvessels, details of snowfall at sea are now available for the first time in these records.
No snowfall was reported during September, October, November, May or June at any ship station, and the Seven Stones lightship, off cornwall, and the Helwick and English and Welsh Grounds vessels, in the Bristol Channel, reported an entirely snow-free season. (February was also snow-free in the Breaksea, Helwick and Welsh Grounds lightvessel reports)
In December snow was reported on the 9th at Breaksea and Scarweather lightships in the Bristol Channel. . . '
Since the Breaksea lightship and the coastguard (probably looking out of his house on Penarth Head at the Passat and Pamir in dock through the falling snow) reported only two days of snow for the season. So by simple deduction the upper photograph was taken on, or after, the 9th December 1949 - "Elementary, My Dear Watson!"