Abandoned House with an Active House

I spotted this house back in 2015 at the back of an active property, there’s an active home, pool, barns etc but around the back is this one house.

Parking up the road, I made a sneaky rear approach and headed into this very interesting little house, I returned a while later to inquire about this house. The owner told me it was his original family home from generations ago and he has tried to get it heritage designation but was denied