Few things to be aware of in general.
- BA Hong Kong check-in doesn't open until 3 hours before departure and in-town check-in isn't available at the moment so a v. long lounge crawl isn't possible if you have bags.
- The flights tend to use Gates 4, 5 and 6 but something in the 28-36 range is also fairly common - haven't seen them any further away from security than that.