I would say it must be very early production from Dundee, never seen another one, that's for sure. If you let me know any ink stamp numbers on the inside case back, I'll see if I can put a better date on it for you.
A #21 movement? is it stamped SCOTLAND on the movement? and brass coloured plates?
Very early watch in what looks like super condition, would love one in my collection one day
Frae Edinburgh, Bonnie Scotland
Affordable and Everyday Watches
My other hobby - Sequence Dancing