Thanks for the references which I have now looked up. All very interesting! In the May 1931 article, one of the toastmasters was A. McGeorge, which also happens to be the surname of Eric Day's bride - May McGeorge - so it is quite likely her brother, Arthur McGeorge.
Another question I have, in the same newspaper on 6 October 1931 there is an advert for a gramophone recital "to be held by Mr Eric Day assisted by Miss May McGeorge (soprano)", but this was 2 years after they were married. It seems strange to refer to one's wife with her maiden name and the title Miss, or was this part of being a member of the "brotherhood"?