Hi Stig,
Clearly this is going to be a difficult machine to identify. I believe we may require assistance from a board user who recognizes the chevrons on the aircraft.
A fw observations. If it is accepted that the serial number is french, then the type of aircraft shown would appear to fall into a batch of Type 5 LAS according to the Albin Denis site at:
http://albindenis.free.fr/Site_escad...ete_Voisin.htm
If it is a french built machine then it is necessary to observe that Italy is not included among the operators of the Type 5 LAS in Davilla and Soltan.
However, the serial would be viable for an SIT built Type 3 LA. What is the highest serial number you are aware of for a V.13xx series machine? As I've already mentioned V.1333 is the highest I have, but frankly I don't have sufficient reference material.
Edit there is a photo of V.1347 of 5 Squadriglia at:guerra-allorizzonte.it/Aviatori/fucini.html if you click on the link for 5a Squadriglia in the text. Also as already stated the serial placement and size is atypical for any Italian built machine of this batch, but again insufficient data is a problem. Do you have WDF 135? Any clues?
At the moment based on far too little information, I incline to a french operated Type 5 LAS, but would happily be proven wrong, just to have certain information.
Regards,
Clint