A very nice thing to find in your house and well worth getting properly serviced by an independent watchmaker (do NOT send it to Omega - the reasons for this have been gone into dozens of times on here). It would probably cost c. £150-200 to service it but it is worth it, and it should not be worn unserviced as that will grind and damage the dried-out internals. Date is probably mid 50s. I have a 2767-5 (see below) with a similar cream dial but different font and dial configuration. I think yours is another variant of the same watch. Mine is from about 1955 according to the movement serial number.
The Speidel band is not original. You could consider replacing it either with a BOR (beads of rice) bracelet or a good quality leather strap. IMO a realistic value for your watch is about £600. It looks all original and in good condition, and those early Seamaster chronometers are quite scarce and very collectable.
View attachment 721984
Click to expand...