Problems with QF1 early March

[Ash W]

For the first 2 1/2 weeks of March QF1 ex Sydney left about 3-4 hours late every day except for Friday the 7th and 14th. Does anyone know why?

I flew QF1 BKK-LHR on 2nd March and it was 4.5 hours late leaving Sydney and clearly BKK. I have just received a letter from Qantas advising that it was due to a u/s aircraft and they had to find another to replace it, which is fair enough, but I don't understand why the delays continued for another 2 weeks or so.

At first I thought maybe there was a problem with some late inbound flights, I understand that the a/c that mid afternoon arrival from JNB is often used as the outbound QF1, but on the days that flight flies it arrived in Sydney more or less on time. Indeed I couldn't see any 744 arrival that was late. So does anyone have any idea as to what the issue was?