I got a call from a local watchmaker two evenings ago wondering if I might be interested in some military Omegas he had in. Well of course I was interested and drove straight round in the morning. I was pleasantly surprised to find this 300 among them and brokered a very reasonable deal on the spot. I would have been pleased anyway but the icing on the cake is the very low serial number - one of the first 5! I live in a very rural area so it's extremely unusual to find good vintage Omega locally although my 2915 was also purchased locally many years ago.
Thank you for all the positive comments. It sure was lucky but making as many contacts as you can cultivates luck!