René,
Maybe unsubstanciated story from your point of view, but I quote it from my side . I am 100% sure that some 769 and 734 branded SINGER were sold on turkish market until 1945 - 1950 , not sure of the limit date .
Here are my reasons .
I personally bought a very early Chronomat 769 SN484114, restoration project condition , on eBay in 2013 - seller was in Greece . It is triple marked SINGER , nowhere on it appears any Breitling brand ....despite it is clearly a Breitling production.
I made my little inquiry , and it is a fact that since 1950( circa ) LG Breitling used the brand SINGER on the turkish market - or more precisely on the Ottoman Empire . It is just 7:30 am and my mind is not enough clear to remember the difference btw ottoman empire and actual Turkey , but it is linked to some events happened in Europe just before the mid of 20th century
I spoke about that with a turkish native watch fellow here and he got similar informations about Singer - Breitling .
I got similar informations from a turkish selller in Istanbul , and I have seen 2 or 3 ( different ) Singer 734 for sale on eBay . On the pics they are really similar to early version of the Breitling 734 - the military version shown in the Breitling EIGHT section of the 1942 catalog .