Hi Peter - nice to see an original owner watch that looks to have been worn and enjoyed for many years. Your watch is a vintage Heuer Autavia 11630 GMT with automatic Calbre 14 movement. The model number (11630) and serial number are engraved into the case between the lugs. To see them you will need to remove the bracelet.
The watch does need some cosmetic work (new crystal) and is worn but the up side is you have the original bracelet and box, both of which will add some good value to the set. Its hard to give an estimate so I would suggest you list it on ebay with a 0.99c starting price. Take good pictures including some of the box (worth around $500 to $700) and bracelet and the market will determine the price for you.
Hope that helps
regards
Paul
www.heuerworld.com