Most visitors online was 1660 , on 12 Dec 2020
No I haven't Jim. Also I'm a tad reticent to explore under the dial..even though I've done it many times before. I just thought someone would recognise it on the off-chance.Piers,
I am assuming you have looked under the balance for a plate ID stamp or under the dial?
Got it....Gruen 581...Piers,
Maybe someone will know what it is,if not unless it has complications ,like day, date, etc the dial is usually just 2 screws and the Balance bridge is just one screw.
Have you compared to Ranfft List ?
bidfun-db Archive: Wrist Watches
www.ranfft.de