I was on board the inaugural SQ319 flight.
We pushed back and started to taxi then stopped. Captain came on and said an a/c had gone tech in front of us so we had to wait for that to be cleared. A few minutes later we set off again and went over to 27L. So I'm guessing this may be one of the reasons we went from there instead. Someone on board said it looked like an LH bird had the problem.
For those working out how they will use the big birds. In May SQ220 from SYD starts to get 744 and SQ222 starts with the A380.
SQ636/637 to NRT goes A380 from 20 May.