Good morning Ken
,
why do I have a nasty feeling that Breguet's may hold the key
Well, it is on there (it doesn't need any log-in to find it though), but it's on several other sites too.
It's not on Wiki, although the designer chappie is mentioned (a single line entry) and he get's mention for his later work on an aircraft he designed for a company he joined in 1916.