It was possibly all just an excuse to get Moriarty back. Because what it boiled down to - as it did, coincidentally in And Then There Were None - is how you can be seen to have your brains blown out by a shot to the head and yet go on to commit more murders. It's all about the art of the accomplice, the illusion, and the morgue getting the right body at the right time.
It was fun, fast and furious, and just a little bit bonkers.
Tyntesfield is apparently "a masterpiece of Gothic revival architecture", which no doubt appealed to the Sherlock creators. It was home to the Gibbs family, who were wealthy rather than aristocratic. That means to say, they weren't posh. It definitely has the air of a home rather than a palace (or mind palace), with its sumptuous red and green flock wallpapers, intricate wooden tiled floors, curved turret seating, balmy pot plants and giant carved stone fireplaces. There is an organ room and a billiards room, a boudoir covered in dust sheets, and a supposedly beautiful chapel which our daughter wouldn't let us look at. Its attic is jam-packed with storeroom "stuff", from frayed old tinsel Christmas trees to piles of chairs to a child's bed left in a corridor. There are musical instruments for children to play, and there is silver for them to polish while dressed in a maid's pinny.
On a practical note, the house is quite a walk from the car park and the ticket office for little legs. It's an even further walk to the kitchen garden and the children's play area, which we did not attempt in the pouring rain. It is recommended that you pre-book your tickets to the house, as they have to limit numbers. Though we had no problem going straight in at what should have been the height of the summer season. However, we arrived as it opened, and the weather was so lousy I think most people were staying at home that day. I expect the lure of Sherlock will put further pressure on visitor quotas. While we were there, we also had a nice lunch in the Cow Barn cafe at Home Farm. Yes, it was once a cow barn. The tables are in the old stalls, surrounded by whitewashed brick walls, cast iron railings, and the occasional stone trough. (No comments about it befitting my child's table manners, please.)