Gijs accounts of the travel invite two comments:
1) The centre of London is closer than Gijs suggests. Swiss Cottage underground station is on the Jubilee line, and to reach Baker Street is only two stops direct, and the following one Bond Street, the heart of London. The travel time is 5 minutes to Baker Street & 2 more minutes to Bond St.
At either station one can change to connecting lines to other parts of the city.
-- There are also numerous buses from Swiss Cottage to the centre and other parts of London, along with 2 night buses, one from the centre of London, the other from east London via Camden.
2) I'm glad Gijs notes the ease and accessibility of Luton Airport by bus. The direct connection is to Finchley Road close to my home. Journey time from the airport to Finchley Rd 50 minutes. -- Finchley Road to my home a 7 - 10 minutes walk. -- There are 2 bus companies that operate buses to & from Luton Airport: National Express and Green Line. Both operate a-round-the-clock 24 hours service, with the former 3 buses an hour during the day, the latter 2 per hour. The former runs 2 buses an hour during the night, the latter 1 an hour. -- One may add that National Express similarly runs a 24 hours service to & from Stansted Airport to Finchley Road, travel time 70 minutes.