Hello DH and I are traveling to London this March. We're flying in and out of Heathrow and staying at an AirBnB near the Turnpike Lane tube station. Our flight back to the US departs at 0700, so I had a couple of questions. First, what time should we plan on arriving at Heathrow? Is the standard 3 hours for international flights a good rule? Secondly, if we did need to be traveling around 3/4 in the morning, what is the best way to get to Heathrow? Does the tube run all night (I feel like I've read conflicting reports). Is it best to just call a cab? Thanks in advance for any insight you may have!