Try a "cone point" grub screw. Lots on Ebay. You shouldn't have to drill the seat post but ideally drill and tap the frame or collar. Bit of red loctite, job done.
Likely a "Ritmo" rather than a "Romany" which was their top of the range tourer. It had dedicated rack fixings and cantis IIRC.
Nice nevertheless. And an early one too, to judge by the seat tube decal.