BA have order more 787s because they are fantastic aircraft.
The fuel savings, engineering monitoring functions and passenger comfort make this an easy choice for them. The battery issue is nearly fixed, why are all the 'experts' on here convinced it's a terrible aircraft? Looks like they know more than all the airlines ordering it. I know some of you are knocking the aircraft because you have an EADS connection or are anti Boeing for whatever reason, but some of the hype and nonsense on this thread is tabloid stuff.
Pilots love the 787, engineers (working with it) think it's great. It's the kind of aircraft operators have wished for. To sit in an operations office knowing what EICAS messages and what parts need to be available for it when it lands is an amazing capability. As a pilot it's a joy to fly.