I was due to travel back to LHR on the A380 in question.
I was in the lounge and decided to come down to board roughly 50 minutes prior to departure. When I got to the gate I was greeted by an empty gate and another pax informing me that the flight was cancelled. I then went right up to the gate and the Captain/FO was explaining that there was some system in place for taxiing into the gate and that it had clearly failed. These weren't his exact words - I'd had a couple of glasses of wine and was pretty tired too.
There was absolutely no mention of the aircraft being towed to the gate and it was implied that the blame did not lie with the crew operating the flight.
Other than that the BA staff, including the flight crew put in a great effort (including the Captain/FO handing out bottles of water and apologising there was nothing stronger) to organise hotels and transport for c500 passengers.
I can't complain as I got another day in the Florida sunshine and an upgrade from W to J on AA on the flight home the next day.