We have a couple of flights booked GLA>LHR>PVG and returning on HND>LHR>GLA next year in World Traveller Plus (Premium economy) The flights appear in Manage my Booking without the option to pay for seat selection. They seem to be in E, and were booked by a travel agent as part of a bigger package. Is that why I can't look at seats yet? Would a call to BA be more fruitful?