A quick google says it’s owned by the landmark trust, which is a charity that preserves historic buildings, so whomever lives there is renting it.
It has had some extensive work already, if you look at the listing images it was looking really knackered. I wonder if it had got to the stage where the charity can’t afford to pay for further renovations.
Price estimates show it should be worth in the region of 750k. So selling for 450 is a huge discount, and indicates it’s got three to four hundred grand worth of work required, or it’s not salvageable long term.
So this isn’t a private sale, this is the charity tried to sell privately and is now throwing it to auction to get rid, and don’t have deep enough pockets to keep it. So they are hoping to find someone who does.