Hi all you guys, really pleased and heartened to see such a great response to my appeal for advice.
Unbelievable level of knowledge on display here, and really saved my bacon!!!
Some fabulous examples shown here by Castle4444 and Cajuntiger ...God knows what they are worth.
Even the movement of 'mine' seems to be in doubt,with the talk of OXG/uncased movements and smudged serial numbers.
It's a MINEFIELD!
I'm not sure if I'm going to ever end up with a '59 (of any kind, not especially Omega or Seamaster) that ticks all my boxes. Maybe an IWC Ingenieur - it has 36.5 mm and as it's thick it might have enough presence for my 8 inch wrist. A really clean one will be heading for 10k though. Not sure about obscure and defunct manufacturers like the Enicar above ...I'd kinda like a classic, but more Omega classic than say Longines classic.
I'm in the right place to find local examples, if I'm patient - Geneva,Switzerland baby!
Again, Thank You guys!