I flew this route arriving in London yesterday, albeit on BA84. The CSD on board asked if we would be using the T5 arrivals lounge on arrival, so I gently reminded her that the flight arrived at 2pm - she suddenly realised she had lost half-a-day from her plans ;-)

As we had two todllers with us, we sat at the back of Club World in 20DEF. My best advice to you is avoid that end of the cabin if possible (because most families would select those seats) and:

- to gurantee seats together, pay now and choose upper deck
- otherwise, check availability just before T-72 (when seat selection begins to open up for some groups)
- if the flight is looking full, pay for seats at that point
- if the flight is not full, take a chance and tuck yourself up by the windows at T-24

The lounges at YVR are above gate 64, the flights usually depart gate 58 directly opposite. There is a small F lounge (if you are entitled) and a larger J lounge. Best to arrive at the lounge at least 45 mins before departure, at which time it starts to become difficult finding adequate space to relax.