I agree, not a great experience, and as someone who also had a faulty CW seat not so long ago, it is disappointing when they don't work properly.
My difference was, that there was no one to swap with, so I had no option to move into another seat. You were given another seat which worked perfectly, but then decided to move back into the broken seat, when in reality, you could have just moved your items to the seat you had been moved into. I appreciate that everyone has a preference over which seat they like for varying reasons of being discrete, or away from a bathroom or some other reasons which are personal to them, but the actual seats are all the same in regards to the hard product in which they offer.
I would be very surprised if you are offered anything bar a small gesture of goodwill, as BA did deliver on the hard product which you purchased.
Was the person in your broken seat sleeping when you decided to move back to it?