Thanks for all of the feedback - some food for thought. If I do decide to give it a go I would definitely go late, leave early and make sure that the place was at least as tidy as it was before I arrived. I did think that it would be very unlikely that anyone would know that I was there at all, however the last thing I want to do is face any legal repercussions (highly unlikely I know.....
thanks for the input re that area sussamb and jimbob) or annoy anyone (the part about annoying folks with guns was in jest
) for doing something just for a bit of fun.
I would be carrying a tent anyway as I guess there is no guarantee that just because a hut is usually unlocked that it would always be unlocked. If I do end up doing this, I think I will pitch my tent outside/nearby, clear up everything as soon as I've used it (e.g I won't leave cooking stuff lying around to tidy up in the morning) so that if anyone does happen to spot me and is not happy with me being there I can just apologise and move to my tent.
The main reason for wanting to do this was just to give me a bit of a focal point when exploring the North Penines, Ive been up and around cross fell, dun fell, little dun fell, melmerby fell, great stony hill, nine standards rigg, high cup nick and a few other places - I love the emptiness and openness of the area but I can't say that many of the other hills particularly excite me, so I thought having a night in these places and exploring other building symbols on the map would give me something to aim for. Just ordered Paddy Dillons book so hopefully that gives me lots of other ideas too.
Thanks again!