Thank you for all your comments, I will try to get a seat by the exit rows, either lower deck or upper deck, if it is possible. I hope I will get an empty seat next to me too...

Ahhh...a long trip to go.

Cheers!!

NB: it stated on my confirmation slip that it is a 744 from SYD-BKK and 747 from BKK-LHR.