I had *exactly* the same issue when I booked a LHR-HKG return, before I realised that there are two BA 744 layouts!!! Take a look at
http://www.seatexpert.com/BA747_38.HTML
http://www.seatexpert.com/BA747_70.HTML
Your layout will be the 38 Club World seat version where WT+ is rows 17 - 21.
PhilH