Thanks for posting this! I had never really been aware of the UJ10, but the moment I saw the first photos I was intrigued. The lugs are Bocama model 14 type II, and they were used on a surprisingly wide range of bikes. Allegro switched to these lugs from Nervex Professionals c.1961; Raleigh used them on certain Super Courses, particularly 25.5-in examples, c.1970; and Peugeot used them on the PA-10.
I've encountered those bearings in Delrin retainers on a c.1972 Liberia. Juvela identified them as being made by Sim, and mentioned they're on page 83 of the 1970 RonKit Handbook.