Hi, I just travelled from Wimbledon to Heathrow terminals 1-3 on my adult unregistered Oyster. I touched in at Wimbledon (at the ticket hall before the barriers, even though they were open) and changed to the Piccadilly line at Earls Court. When I touched out at Heathrow I noticed it had charged me £11.50! Maybe I'm missing something obvious here, but I'm quite upset as I checked several websites and they all said it would cost £5.50 maximum, even at peak time. Can anyone shed some light on this?