Just checked Dave's Strava from when he surveyed that part of the area (26/1/18). This confirms what I assumed : Dave never visited the area where #12 and #13 were sited.
Can't understand how the Controller could allow the Planner to use this area.
That makes me feel better - I thought I must be going mad!
In addition to the mapping issues (which I didn't encounter), I think the flag was hung slightly WSW of where it should have been, based OJ's GPS trace with mine.
It was very close to the bright yellow (mown grass) around the castle. I came back out that way when I went back to check it.
Happy to make you feel better OJ. I'm sure you weren't the only one I made feel better with my run yesterday ;-)