Trying to figure out the CW seat configuration typically used on the PDK to LHR route. My travel date is June 4, 2023 on BA flight # 266

This route typically has just 3 levels of seating. From what little I can gather the plane will be a 777-200ER and one of the three following seat layout versions: (77L,77S, or 77T). Would anyone be able to narrow down which plane version?

Also information on the load in CW at the present time would be much appreciated... thank you for any information.