Walk to the central bus station at Heathrow, which is a 10 minute walk from Terminals 1 and 3. Most buses also visit Terminals 4 and 5, but not all of them, there is a free train connecting from these terminals to 1 and 3.Get on the bus, and pay the fare.Allow at least one and a quarter hours for the journey.hough there is no direct route this way, the underground runs from Heathrow into London, from where you can catch a coach or train to Gatwick. Allow at least 3 hours travel time. Direct routes are the Gatwick Express from Victoria, or the National Express coach.