“The Man From Yesterday” is a John Wyndham mystery. The story appeared in the v105, #2752, March 28, 1959 issue of John Bull. (Thanks for the scan, Bill.) I can find no mention of the story under another title in ISFDB or The Fiction Mags Index (my go-tos). I have scoured his story collections for any tale that begins with “On a day in late December of ….” (the date could be changed, of course). Nothing.
The plot of the story has the narrator, Reginald Aster, approached by an overly curious lawyer, Mr. Fratton of Cropthorne, Daggit & Howe, about a bequeathing of a large fortune. Aster admits that he only every met the man who left him a fortune once!
The recipient of the money reveals what happened later at the club. He met Sir Andrew Vincell on the street back in December. The old man seemed confused so Aster took him into a hotel bar for a few brandies. While there the old man seemed fascinated by his elderly appearance.
If you’d like to read the rest, please check out Monster 2: From the Pages of Dark Worlds Quarterly.