Seeking advice - in transit at LHR can I leave the airport?
I will be flying VIE-LHR-SYD this Saturday. I was thinking of changing the VIE-LHR leg so I could arrive early and do a bit of a day trip (flight LHR-SYD is in the late evening). I don't believe I would be falling foul of any security rules but grateful for any advice to the contrary. Thanks!