Hi,
AS a BA Gold you will get access to all the Cathay lounges ( even in PE)
My 2 recommendations are
The Pier ( by Gate 61-63) -I personally prefer this one
The Wing ( by Gate 3)
Lots of information on the Cathay and BA forums and
https://www.cathaypacific.com/cx/en_...t-lounges.html
The Amex Lounge is pretty good also .
If you have a lot of time you can lounge hop.
Regards
TBS