Kate and Crispin's home was absolutely wonderful during our Christmas holiday to London. It has a great kitchen with a professional range and two ovens (that enabled me to make a lovely holiday meal of lamb, ham, and all the rest). Tub for the kids, shower and en suite for the adults, great common areas. If you're an iPhone users all the electronics are geared for you (Sonos, iTV, etc) and the wifi was pretty decent.
They have a smashing garden that I'm sure is amazing in summer (a little wet for December). Very impressive space in the city if you have kids.
Very close to the Jubliee line, and that gets you into the heart of town in about 20 minutes. It's about a 5 minute walk to the stop, more like 8 with kids. Willesden Green is a great little local center with two Sainsburys and a Coop within walking distance. For longer stays like ours, Costco Wembly is two stops away and £12 Uber home. Pro tip - do that when you first get there, not 3 days before you leave like we did!
Most importantly, Kate was incredibly communicative and gracious with hosting. We talked on the phone, she emailed to check in often, and was just lovely. She left out Christmas decorations for us to trim our own tree! I can't thank Kate and her family enough for opening their home to us.