As pp have said, people who are wanting a house like that might be put off by the other houses on the same street being less impressive. The house looks out of place on that street, I think, although I haven't looked at the street view, just the photo showing the next door houses.
Going for black window frames etc, was a massive mistake, imo. It's not in keeping with the heritage of the house, and makes it look much less appealing. Obviously the windows are a magnificent feature of that house, but the black frames take away from the windows, rather than showing them off in all their fiery
Also, as a pp has pointed out - you would expect a house like that to have gates, or an impressive front garden - it looks too modern and average for the age of the house, especially when you couple the age of the house with the price tag.
Inside though...wow!