The term "listed building" makes me sit up and take notice. May I ask how big the house and the property are, how old it is, and what you mean by "outbuildings"?
Basically, a larger apartment always means more work (even the unused bathrooms have to be cleaned at some point, and dust also accumulates in unused rooms. In addition, every room costs money (property tax, insurance, heating costs, maintenance, etc.).
Personally, I find the jump from an apartment to a house quite significant, because you also have all the surrounding things. On the one hand, the previously shared rooms, and on the other hand, of course, the property. Just mowing the lawn and sweeping the street/path can already be very time-consuming tasks, especially if you are reluctant to do them. With old houses, there is ALWAYS something to maintain, which usually used to be done by the landlord or the property manager. This costs not only money but also quite a bit of time.
However, I have never had the problem of having too many rooms. You can always find something to do with them (fitness room, sauna, home cinema, Carrera or model railway, ironing room, office, archive, workshop, library, party room, fireplace room, etc.). Only with bathrooms can you often not do much else, as they are quite specific and usually quite small. Tearing down walls is also very difficult in old buildings, as there are usually load-bearing structures and supply lines within the walls.