It is an Autavia ref 2446 with the 1st execution dial, which is particularly rare. The hands are replacements from later models, as Gavin noted. The value is difficult to establish, as not many change hands, and the price is particularly labile right now. A two-dial version with correct hands recently sold at auction for USD25,000. Now, that was an extraordinary result, as previously these changed hands in the USD3000-6000 range, and not enough time has elapsed to determine whether this was an aberration or a breakout for the values of this model. I favor the former - it was a crazy price.
According to Rich Crosthwaithe (
http://www.heuerpriceguide.com/#/autavia-60s/4561090754), this would sell for about GBP5000 with correct hands. You'll want to discount a bit for the hands.