Caroline's place is as good as you can imagine when reading description. It is beautiful, fully equipped and has a great location about 3 min from tube station Holloway road of Piccadilly line. With this line by the way you can go directly to/from Heathrow airport. Also, Holloway Road station is about 10-20 minutes from the very center of the city and most must-see places of London.
All check-in/check-out procedure was smooth, we didn't meet Caroline herself, but it made no problem at all. Me and my girlfriend have stayed at Caroline's for a week and everything was great. I would definitely recommend it to a friend and come back myself if visiting London again!