As it happens I'm in a similar situation. I have a Yema Chronosport that I bought back around '71-72. Didn't cost much, started to play up some years later, bought a TAG Series 1000 and left the Yema in a drawer. Bloke I worked with is a watch nut, and has loads of watches, including some like your Omega. Sent the Yema to a specialist he uses who's quoted £245 to get my watch up and running. It's twelve hours work, and he reckons it's worth around £5-600, and I've found one for sale on'tinterweb for around that. It's a lovely watch, all stainless, so I'm going for it. It was the first quality watch I bought for myself, and they are rare, the company was bought by Seiko in the eighties. Sadly, if it had had a different movement it could have been worth £2000!. It's mechanical, so replacing batteries not an issue…