A while ago I stumbled on a reference to a letter, co-signed by Tolkien, published in The Times for Friday, 28 January 1949 (page 5). This letter isn't referenced in any of the usual sources, so it makes for a minor discovery. The letter is signed by Tolkien and nine others, comprising the Honorary President of the Newman Association and nine Honorary Vice Presidents, the latter including Tolkien. The letter registers protest at the arrest of the Cardinal Primate of Hungary by the Hungarian government.
Tolkien's affiliation with the Newman Association was previously undocumented. The Newman Association was founded in 1942, and continues to this day. (See their website here.) Tolkien's involvement does not seem to have been extensive. I am grateful to Dr. Christopher Quirke, Secretary of the Newman Association for looking into the matter and conferring with his colleagues. He reports: "I made enquiries and saw numerous letter headed paper for the Association during its early years and Tolkien's name does appear in a long list of Vice Presidents that we appeared to have during those early years. The Association was founded in 1942, for Catholic university graduates, and Oxford was prominent at its foundation. I can't say more than that. I don't know, for example, how involved he was with the Oxford circle."
Tolkien was unquestionably very busy professionally all throughout the 1940s, but it's interesting to note that for a time at least he managed some additional volunteer work for the Association devoted to John Henry Newman, founder of the Birmingham Oratory where Tolkien himself had been educated as a boy.