I also beleive that on the LGW beach fleet at least the W bulkhead's are all bassinet postions.
Perhaps the two aisle seats in the middle block aren't but if not they are reserved for GCH's. I had some issues very recently that I had to get exec club to the phone to resolve, Master RD was "assasigned" to me so I had t take the bassinet postion but Mrs RD is only Bronze and couldnt select the seat next to me.
They sorted it for me with a quick call but im hoping to UUA so hoping it wont have been needed!.