I'm starting to feel a bit paranoid about connecting from Gatwick to Heathrow. Plane lands in Gatwick at 945, that gives me 30mins to get to the National Express stop to take the bus to Heathrow, if I miss that one I need to wait an hour. My international flight is at 215, that should be enough time, but what if there isn't? Shall I take an Uber/taxi instead?