Trawling through my Picasa images, I found this:
A sketch of the landscape showing the river Esk continuing to the Forth at Musselburgh.
There is a lot of established geometry, and also some speculative stuff, which I haven't verified yet.
The horse and rider are shaded green, and I have left an area clear, as at the time I was unsure whether there was an additional feature still to be recognized. There was discussion about what else might be there, different people were asking if I could see this or that. One suggestion was two riders, a Templar symbol, and the area I have left perhaps owes something to this idea, but I am not convinced and it was a few years back. Just one of those threads which got laid aside, one of many!
Yesterday I took a photo of a map I have with the feature drawn in. Unfortunately, I can't get the camera to connect to the computer to download, for some reason. I'll get bak to it soon!
ps: If your eyes start to spin, welcome to the club!