Very interesting. And an appealing watch, to say the least. Without seeing the serial number, the 1959 date would have to be taken with a grain of salt.
I just realise that the crown doesn't look correct for ref. 9000, neither the shape of the lugs (too pointy - except if the case have been brutally polished)
This little puppy is in transit at the moment. Not too much info out there about these that I could find. So far looks good and will see what I get. Sellers pics.
Intriguing watch. Given the high asking price of 3845 GBP, I would certainly try to ask Longines for information about the original dial before purchasing. I could believe that the dial is correct, as Longines signed these ref. 9000/9006 dials in a variety of ways including "Conquest", "Automatic", and "All-Guard Automatic".