My problem with old maps and gateways continued after I'd sent in the post. Found another map, this time drawn from the English perspective. A tad disconcerting in that the artist had obviously been sitting on a ladder at Leith and drew everything the other way around to the previous maps I'd seen. But it was dated 1544 and was drawn by the attacking English as they arrived to raze Edinburgh to the ground - exactly the time of my story! The map is in the British Library rather than the National Library of Scotland. It showed men attacking the gate - the Water Gate - yippee. I rushed off and re-wrote bits of the chapter to fit the new information.
Unfortunately it did not show the mysterious vanishing gate on the south side of the town. Even if it was there when the English artist arrived, it would not have shown on the drawing, since it was drawn from the northern side. So, I've sent my hero another way - possibly using a bit of poetic licence, but I'm writing fiction after all. I almost started another hunt but decided to leave well alone. The pieces I found declared that no one quite knew the extent of the Nor Loch nor how long it had been there. They knew when it vanished (or drained away) but according to some it appeared rather suddenly in the 1400s, as a defence against raiders from the sea. Other reports said there had been a lake in much earlier times. So my hero got his feet wet.
Amazingly my car reported an outside temperature of 17 degrees today when I was out for a walk, and it was gorgeous in the woods. The sun slanted down through the branches and the pathways are covered in gold because the wind had brought down all the yellow pine needles at once. (Actually they may be larch or spruce, but they look wonderful.)