Have a look at the BA Forum Dashboard - this has the main threads in it, and section 5 has the seating guides, including one for the 787s.

I'm quite happy in row 13 but it's the case that you typically won't be early served. It shouldn't make a difference to food options, due to the standard process for CW meals, but you may be aware of how quick WTP get their food - very quickly usually - before your food appears. The other 2 disadvantages of those seats - not a enough to dissuade me - are (a) not much of a view, the wings on those aircraft are huge and (b) possible proximity to a noisy toddler in WTP just the other side of the partition - not that it has ever been an issue for me.