Tavistock Manor is settled into a lovely huge estate for a rental property, requiring a fair staff of gardeners and groundskeepers to keep it looking decent. Thus the property seems to have waves of excellence and decrepitude, depending on finances of the owner and renters. The property as a whole is generally too big for anyone but the richest noble to purchase, and unfortunately its reputation as a rental property makes it unpalatable for most who are concerned about their long term social standing in the region.
Thus it remains a rental property for visiting nobles, adventurers and merchants on the up-and-up, and strange visitors with more money than sense.
You can get 300 dpi versions of the map of Tavistock Manor with and without grid at https://rpgcharacters.wordpress.com/2015/07/31/friday-map-tavistock-manor/