The OP will hopefully confirm, but from the fact that they declined a downgrade I inferred the cabin to be full.

Of course, a CW seat would recline, but I assume that was not the thrust of your question.

FWIW, I would agree that an alternative working seat in the same cabin would be acceptable, but it seems that wasn't possible here. And from recent personal experience, BA seem to be treating all failed F seats as similar in terms of compensation.