Just wanted to add for the less-familiar - the food at the QF lounge is at the sit-down bar - first floor! In the earlier days I've been always wondering where is it only to be met with a measly generic buffet upstairs - it's downstairs, with a menu to order off from.

EDIT: Also, if you're on 159 to BDA, and arriving on 262 from RUH - which means you arrive really early at 05:30ish and depart mid-afternoon, a lot of things in London aren't exactly open early enough for you unfortunately. That being said, if you can afford HEX (or Liz line, but it might get crowded) on a quick jaunt into central London, then a nice walk around the City, I think it's well worth it compared to more time in lounges, and it would definitely be a contrast to Bermuda or Riyadh.

But if you prefer to stay in T5/T3, much easier to go round covering all of the lounges like some of us insane people like to do 'round these blocks