Mum and Dad photographed this phone box for me a couple of weeks ago.
(Coordinates 55°82’87.2″N, 3°27’31.0″W.)
This is a fairly well-kept one. The paint looks much fresher than most phone boxes, and there still seems to be a working phone inside. Hopefully it will be around for a while!
Update March 2022: I’ve recently heard that the Silverburn phone box has now been granted listed status! Here’s a Facebook post about it from one of the local MSPs. (I’ve also added the coordinates as apparently I forgot to do that when I first posted this one!)