Buckland Abbey.

A fairly long day out to said Abbey (please see first extra.) Although not a particularly impressive building, it had some interesting history. Acquired by the Grenville family then later by Drake (he of the Armarda fame) before eventually ending up in the National Trust's care.
Main: Said to be haunted by a monk, I was lucky enough to catch a quick glimpse. If not, it may just have been one of the in costume guides. 
2nd extra: The rather large medieval barn. 
3rd extra: Abbey drystone wall.