[Arran]

 That's one of the problems with some transistor sets imported from Japan from the late 1950s through mid 60s was that they were private label jobs without a manufacturer's name. Some of them were sold in drug stores and discount department stores, some used names of defunct old American radio companies from the 1920s and 30s . There must a way to track down at least some of them I think, SITCO is not one I am familiar with though.
Regards
Arran