Hopefully I won't get thrown for this but doing a search on the British Airways forum at
Flyertalk might be a help.
IMHO, much of the Club 777 seats are similar in overall preference. There's no coveted upper deck like on the Jumbo for example.
"Old" Club is in a 2-3-2 so anything apart from the middle, i.e. the window is fine. New Club is 2-4-2 so again a window or aisle would be best.
Some people suggest that a seat as far forward as possible is preferable due to noise from bassinet seats in World Traveller Plus.
Incidentally, some have likened Club on a 777 to a dormitory, due to the large single cabin and impression of a vaulted ceiling!