One of those eye-popping snippets from the archives of the Socialist Standard:
"Glasgow branch held another big meeting at the Central Halls, Glasgow, on Sunday evening, March 8th. Com. Higgins was the speaker, and reports indicate that the Branch's efforts to ensure a good attendance, literature sales, etc., were rewarded with success. Perhaps the high-light of Glasgow branch's activity during March was their annual dance, which took place at the New Astoria Ballroom, Sauchiehall Street, on March 12th. Over 750 friends and sympathisers enjoyed themselves at the dance."
750?
With figures like that there's an off chance that one of my relatives was there doing the jitterbug.
Link: Party Notes and News (1942)