I met the Passenger Services Director for Govia, Stuart Cheshire, again this afternoon and was given some slightly more encouraging news. He said that from today, Govia will be advertising an interim timetable on the various rail websites and all advertised services will run (barring unforeseen circumstances such as last minute driver illness). So passengers should be able to have confidence that a service that is shown will actually run each day. In addition, extra services will be introduced to the interim timetable as more drivers finish their route training.
GTR is planning an improved amended timetable and I will ask for regular updates.
I welcome, at last, a level of certainty that will allow passengers to plan their journeys.
Further discussions about concerns over the May timetables are continuing.