Hey! Flew this route recently in WTP.

The A380 is new WTP with a better service in my opinion. Get a hot towel after take off, sparkling wine as a welcome drink, better mid flight snack brought to you like ice lollies etc.

Came back on BA 28 which unfortunately was a 777-200, with old style WTP. Cabin crew were great as usual however you do miss out on new seats, bigger screens amongst other things. Did however have a row of 4 seats to the two of us!

I believe BA do/did fly the 777-300 ER to HKG as I remember there being new WT and WTP hard products last year but this was pre-A380 so I don't know if they made a switch when they got rid of the 747 to have a A380 and 777-200 serve this route. Might have to look into that?

Don't think it matters on the way back as it's a half hour difference in take off but I can understand why you want to find out on your outward journey with a 3 hour departure difference.

Hope this helps! And have a great time in HK!