[Arran]

So the "M" in the grille must stand for "Mystery" brand? I thought maybe it was a "Minerva", but they all look different, and I don't think that they employed permeable tuning in the front end. However between the tube lineup, and the permeable tuning, I would take a guess that the set is post war, between 1946 and 1950, there may even be date codes on the components. There were a number of what we would now call "startup" radio manufacturers that made sets for a few years, Minerva was one, Telesonic was another, some look like they were made with war surplus parts like Micamold caps, or oddball numbered tubes, but they faded away as T. V started taking off.
Regards
Arran