Apologies for not understanding that I couldn't embed a photo of the watch.
Always "watching", many thanks for the info. I'll read up on the Vacuum Chronometer Corporation.
Here's a link to a photo which will hopefully work and give you more of a clue...
I've just read the article and looking at the pictures of the vacuum chronometer in the article it's clear that mine is one of them. It has the same distinctive bezel clamps at 12 and 6 o'clock, which the article states as the key feature in recognising one.
So I'm guessing (I'm no expert) the watch is probably from the late 60s, before the rise of quartz watches in the early 70s.