Thanks for the steer. I tried the airline and Heathrow websites first, both show touchdown as arrival time, under 3 hours. Imagine my surprise. Flightaware (free) shows on stand time, over 3 hours, exactly as I recall. Flightradar shows on stand time as exactly 3 hours but the track log shows the plane still moving five minutes later. Which doesn't engender a lot of confidence in the impartiality of Flightradar.
Last edited by SLF3; 27th Jul 2018 at 20:43.
Reason: Expanded