NEO operating not only on T3 routes, it seems, but MAD also:
British Airways on Sunday (15APR18) inaugurated Airbus A320neo aircraft, which saw the aircraft operating London Heathrow – Lisbon route. As of 17APR18, planned British Airways A320neo operation in summer 2018 season as follows.
London Heathrow – Budapest
London Heathrow – Lisbon
London Heathrow – Madrid
London Heathrow – Warsaw