I saw this story about a decade ago, but I only re-discovered it now. H.R.F. Keating's "Jack Fell Down" features Ariadne Oliver's detective Sven Hjerson. I saw it in either Ellery Queen's or Alfred Hitchcock's Mystery Magazine, but it turns out it's part of a collection called A Classic English Crime: 13 Stories for the Christie Centenary, a collection of stories on Christie-esque themes. Has anybody read this?