Without the dairy operation I'd suspect they'd have less land, less beauty, less reason to live where they are - the workers cottage wouldn't be so charming if it were on the edge of a lifestyle block 15 minutes from the city. Don't discount the value of their investment!
Yeah, the Adam Smith, purely financially motivated thing to do would be to sell the cows and charming old barns, move out of the ancient manor farmhouse and make a fortune from renting that out as well.
But the life satisifaction of being a hotelier compared to someone who works the land and raises livestock would not be nearly the same.