Thanks David, but a bit too much effort for me to follow up, and I don't do FB anyway. Had it been local (or even local to you, as you're not too distant from me ... and even less from my daughter I think!) I might have taken a punt.
I don't claim to be an expert on this, but I don't think "Magna" is the model of the horn. It was a trade association that some of the manufacturers around that area (Czech/German/Bohemian) belonged to. My Franz Köhler Empor baritone has "Magna" on the bell because he was a member. I think there's some more info about Magna on bassic sax - pretty sure that's where I read about it.