Penny's apartment is lovely, everything is clean and really nicely decorated. She has this wonderful touch for details and it's really nice and surprising to find all the food for breakfast or 5 o'clock tea. (Thank you Penny!). Location is great if you need to stay in Barnet like we did. It's also close to the subway - quite a long ride to central London but the Northern line is very useful to get to many places without changing trains, and you can sit all the way as you board in the first stop!
You should be aware of two things. (1) The double bed is rather narrow. I think it's a British queen size, I guess something like 1.30 m but I didn't measure. It might not bother you but for us it wasn't very comfortable. (2) The way to the bathroom involves a lilliputian door.. even my 10 years old son had to bend. I hit my had twice :)
I still think the apartment is great but I think it's important to be aware of these details as for some (maybe more elderly) people, there may be a problem.