Many thanks to all that helped bring this little beauty back for me. I've got a very nice historic potting shed for the moment but at some stage we will hopefully have a very nice vintage camper also.
Having acquired the #1 Airstream I also seem to have acquired the #0 if there was such a thing. I've been advised there was a #00 owned by the Andy Anderson family, personal friends of the Byams and the Schwamborns but can't find anything on a single zero. The number was very old and clearly there was just one digit front and back. They had been covered over by a few layers of other stickers.