Just discovered an interesting feature when adding my two penno’orth / sticking my nose in to this topic:
I fired up Dronescene and entered Mow Cop into the search. It took me straight there and the National Trust layer was on by default.
So there is plenty of non-NT land surrounding the castle. I went to measure the nearest point that could be used as take off site. The start of the measure pinned to the map but I couldn’t get the other end of the line to “stick”. on the castle.
When I switched off the NT layer I could measure with no problem:
and then had to check by switching the NT layer back on
(The large mouse pointer I use due to worsening eyesight obscures the wee distance box so I need a “sticky” line)