Until I saw that 1958 picture I too was unaware of any other runways (I did enough circuits there) but looking at the ILN picture above you can just make out faint outlines of one at the top right of the island. Of note, the guns in one of the picture were near what looks like an old dispersal in the same area; the islanders said that they had originally been part of the island's defence and had been properly mounted in an emplacement, which was then blown up when the anchorage was abandoned at the end of WW!!