"Philippe" on the chainstay may be Philippe Deleye who rode for the Fangio team.
This post (in another place) has relevance:
https://www.lfgss.com/conversations/163006/
Can it be that all three of our frames were ridden by him - why else put the name there?
Edit: found this ad - also says Philippe:
https://www.gumtree.com/p/bicycles/b...80-/1372902883
Guess he was their best guy.