BTW, had you seen that Jane's 1913 has been published in the web
The current challenge probably just missed being included though i've not checked.
Will check the thread again in about an hour but to summarise clues ...
1913 design
Not French
Unusual radiator for first V6 then V8 engine
Manufacturer went on to have a long but interrupted history in the industry ..........and (new clue) including several previous challenges.
And to respond to RegDep's submission, not the Avro and not British - or Australian.