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I'm a little surprised that your watchmaker hasn't seen an 806 earlier than 1959. 60s are more common but mid 50s and on aren't that rare. That said, these first generation Breitlings are just gorgeous - I'm still waiting for someone to come on here and ask about their 1952 so that I can value it and $20 and then buy it from them for $50
I will second br549's recommendation of Craig's work, but if you are happy with your watchmaker then I'm sure that will work too. Breitling do service vintage pieces in some locations, but not in North America. They have a 3rd party approved service agent - Mark Heist at Horological Services in PA. He's effectively 'factory authorised'.
Oh, and I think it was actually spelled Malton Airport.