And there's a bit in Lowfield for May 2004 which says "Lilian is doubly thwarted: Caroline has refused to let her take Matt around the Dower House, her old home" and later "in the face of Caroline's refusal Lilian has borrowed William's key and let herself and Matt into the Dower House".
So presumably Caroline owned it at that point?
(I haven't been ploughing through ancient Lowfield, honest; out of curiosity I put a few representative words into Google and that reference popped).