BA have done this to us as well on a flight to UVF in summer- we were a group of 5 in CW and they had put us in 1D,2EF,3J and 4A, even though the second cabin was completely empty on the seat map and there was space in the front cabin for us to be seated together! They also sat me and my Dad in weird seats in CE going to LGW from JER recently- he has an aisle preference and I have a window preference, yet they put him in 3C and me in 1F- even when 1D was available!