Looking for thoughts on how a recent situation was handled...

We were travelling home from JFK on 17/11/16 on the BA172. The aircraft was originally scheduled to be a 777 and my OH and I were travelling together but on two separate PNRs. We allocated seats together, but an aircraft change to a 744 meant that we were separated, I on the UD and he on the LD. I am GCH and he is a SCH.

I called BAEC and there were no seats together for pre-allocation. At OLCI the situation was the same, so I assumed we could sort it out at JFK. On arrival, we were advised that the flight was overbooked and there was nothing that could be done.

I have become quite frustrated and disillusioned with BA over the last year due to the declining onboard product and for me this was the icing on the cake. I asked at check-in if the passenger next to me or my OH could be moved/op-upped but was told that it wasn't possible as the flight was full. Only after making a bit of a fuss were we told that they were already asking J pax on the 172 to switch to the last flight of the day for $400 each. We would have taken this option if we could have made the timings work for our onward journey but sadly it didn't. We were not proactively offered the option though. We asked about moving to other flights and were told that they were also full or did not have two seats together.

We went to the lounge and a lady there said she would try her best to re-seat passengers and accommodate us but when we received the boarding call we were told that despite paging passengers, none had come forward. I haven't been on the other side of this so I am not sure how it works in practice? I have had my seat changed for 'operational reasons' several times before but haven't been paged or advised, I just get a new BP when I board and the scanner beeps.

I'm somewhat ashamed to say that when we boarded I got slightly emotional to the CSD and explained the situation. She asked the passenger seated next to me (travelling solo) if he would switch with OH and he agreed. I apologised profusely to the CSD but she said that it shouldn't have happened in the first place and not to worry. I wish I could find the passenger and thank him. My OH asked the CSD to please look after him as he did a generous thing.

Would you (as a GCH on a full fare J ticket, travelling with a SCH) expect BA to have been more proactive in resolving the situation? Or were we overreacting in our expectation to sit together for the flight? Should decisions like this be best made by cabin crew or dealt with by the ground staff?