Word of warning: I've found a new website for textures. Be prepared for wallpaper!
This flat is based on an actual, existing flat in London, which I found on Foxton's. I saw it and I went 'yes, the Holmes family would dig that'. This is where Siger stayed when he was in London, and where the brothers sometimes went for their exeants from school. Mycroft lives there now.
The Penthouse can be accessed from a private lift (which is in the lower right corner there) or through the main lift or stairs, which aren't on screen, but are somewhere around there. I imagine at one point at least one of the bedrooms had two double beds, so it could accommodate the children, but Mycroft had the place redecorated and now there are just three king-sized beds. If the whole family wants to be together, which is rare, they would use the Townhouse.
Everything is in shades of brown, because that's really how I pictured it. I don't see Mycroft as a very colourful person, in fact, quite a non-descript one, so the interior designer decided to go with a very neutral palette when she was hired to fix it up.
The first image is at the bend facing right, the second is at the bend facing left. In the first image, the door on the left goes to a bedroom, and the door straight on goes to the kitchen. Then we have the front door from the private lift, and the front doors from the hallway. The texture for the rugs was stretched a little, so it looks pixelated. Sorry about that.
In the second image, we have the phone on the plinth, the entrance to the living room, the door to the 'cloak room', the door to the office and the door to the master bedroom.
This kitchen came as a full model, with all the trimmings. I just added the island to the room and decorated the walls and floor and put a few bits and bobs around.
The door goes to the ensuite loo. I haven't rendered any of the loos, because it's so hard to get a camera in there and come up with a decent view. This is the bedroom that Sherlock favours, though he liked it better before it was redesigned.
This is Mycroft's room. The loo is behind the door on the first image, the door on the second image goes to a walk in wardrobe. I placed the telly so that Mycroft could flick on the news when he wakes up in the morning and not have to get out of bed.
This is Q's preferred bedroom, as it doesn't have as many angles.
A not very good view of the office, which is hexagonal, with a lot of windows. This is Siger's office, and Mycroft didn't change anything when he took it over. There a few bookshelves behind the camera.
Not gonna lie: I'm pretty fond of this room. Except for the stupid patio door which rendered like a mirror for some reason I can't figure out. There's a small table and chairs on the balcony, but you can't see them because of the mirrored door effect.
One of 'Q's pianos' is next to the dining room table, and there is a small wet bar as well.