I brought my family (wife and 2 kids) for an extended trip for four weeks to London. It should be noted this is not a personal residence, but a managed "corporate" apartment/flat that comes with weekday, daily cleaning service (which was great). The penthouse flat was roomy, and had everything we needed for our stay.
We particularly liked the area. 3 minute walk to Exmouth Market, and a 5 minute walk to Leather Lane. Lots of pubs, cafes, restaurants within walking distance (Clerkenwell).
There are two tube stops that are within walking distance: Farringdon and Chancery Lane.