I've just booked LHR
for May, and the window seats are 50/50 on the LHR
flights at the moment. I couldn't get the seat I wanted so settled for the back row instead (might regret that). It depends how you've booked, the first time I flew QF
, I booked a trip via QF
Holiday so I was able to reserve my seats. Now I'm a Silver QF FF
so get to book my seats at the time of booking.
You've got two long flights so for the sake of a few more dollars I would pay the extra now. Otherwise you may struggle to get three together on the day or even on-line 24 hours before, as I've noticed a lot of people like picking the window or aisle, leaving a hole in the middle for single travellers.
If I can offer one bit of advice, study the seating plans on the QF
website and pick three or four options. I doubt these seats are available now, but look in the rear section of the A380 .....row 80A and K....the best seats in economy......but don't tell anyone OK