Last Sunday the HCon services were completely cancelled. This meant that there were no T4 shuttles either. How did airline pax get to T4? The same may happen again this Sunday and indeed every Sunday for some time.
The HEX and HCon are supposed to be reliable services for Heathrow for justifying the third runway. ...
The third runway is still a little way of opening, and there should be plenty of time for Heathrow Express, Heathrow Connect, and Elizabeth line services to get through their current completion and restructure phase prior to the first plane landing there.