In WAW at the moment and noticed yesterday one of their 787's doing what looked like ground tests/apron taxi as we touched down on BA from LHR.
Spoke to Aviation interested cab driver today and he said there have been 15 reported problems with the the two LO 787's since inception resulting in cancellation and return to homebase.
I'm sure these are teething problems like with any new airliner. At least I hope so. Last year when we went to Seattle to pick up BA's latest 773 (G-STBF) I spoke to BA Director of Operations (nice gentleman) about the fleet among other things, and he said that BA specifically and exactly for the above reported problems will not take any 787's before no. 100.