Fountains Abbey is National Trust. Well worth a visit, it's on my list for when we're back in the UK. There is an intact manor house on site, Fountains Hall, which contains staff flats, so I reckon that's where your friend would have been staying. Intriguingly, I think members of the public can also book overnight stays in that same building...
Thank you, that's prompted a train of thought that has never occurred to me before: I did a fair bit of re-enacting in my teens and early 20s (we probably know some of the same people, especially if you were ECWS or Federation of the War of the Roses), staying in all sorts of old properties, and yet I cannot bring to mind a single spooky experience. Granted, at the time, I was completely lacking in sensitivity, and mainly interested in alcohol and the concept of female company, so I wouldn't necessarily expect to have noticed anything myself, but neither do I remember any stories from other re-enactors about odd things they had seen. And some of them, you know, had been doing it so long they had more experience than an actual pikeman, what with the Civil War only having lasted 8 years...
You might have expected somebody to have seen something. The scariest tales I heard round the campfire were to do with bodged procedures at Sellafield.
On the other hand, if you're expecting to see people in period costume, how would you tell that one of them had been there a little
longer than the others, assuming they don't start walking through walls etc.?