Yeah me too .. Airports are the only place I've had this problem really .. and it's more of a pain since when it does happen they don't cancel immediately and then you have to waste more time getting another driver to come ... Normally a very happy Uber customer, but in the airport I never seem to have a great experience .. I'm also in the Balham area and I've had this happen from LHR and from LGW too ( which would be an even better fare you'd think!)