Hi @stdape, you probably know far about all this than I do, but I'll share the little I know.

I have a Helvetia from the early 1960s. I was in a similar position to you and couldn't figure out how to get the movement out. In response to patient coaxing from this forum I eventually did manage to remove the front bezel and take my movement out that way. I spent ages looking with a loupe all round the front bezel and was convinced there was no groove, or cutout. I never did see it, but I was able to feel a slight flattening. I worked in that area with a razor blade, then a Stanley knife blade, then it was off. I just needed to clear up the blood and I was away.

I hope this helps, and I'm sure the experts will be along in a minute to tell you that was all wrong!

 

You are probably right, i have tried with a stanley knife, the watch is in a real grubby condition, and looks like a previous attempt was made before i purchased it. The winding cogs were wrong way round ! . Will keep trying hopefully no blood lol.

 

Well managed to get apart in end, got crystal out , pushed movement out, very tight due to dirt. I reckon it is somebody's reject watch, Balance Broken, Winding Cogs in wrong way, and the Centre Cog which holds the hands was jammed, broke the stem. Its only a cheap watch couple of quid so no loss, parts can be re salvaged.

No idea on movement only got 556 on it, i guess that means something.

Good for practice, see why it was cheap on E-Bay lol. If anyone can bring light to the 556 be grateful too know