Don't think so, the sign is on the SW Coastal Path - no yurts anywhere in the local vicinity.
That was my initial thought......Halloween ghost in flouncy shirt ahead warning....
That's a plausible explanation. We did see a couple mincing along.......Proceed but only in a camp manner.
IGMC
I reckon its this temporary campsite?.....
https://www.nationaltrust.org.uk/heddon-valley/features/camp-at-heddon-valley-this-summer
Apart from it being circular, instead of square like all the other NT signs.I think National Trust and the style looks similar to others.