LM, many thanks, I did, and I'll see how I get on when back from my travels...
Sabredog, it is indeed the Voisin 10 CA2, photographed at the fabulous museum at Le Bourget. One engine, but so far as I can make out, two separate throttles for the four butterflies - if anyone knows more about the throttle arrangement, I'd love to hear.
Sabredog has control!