Bloody disgrace.
It'll make no difference to BA but on principle, I've decided to make future bookings on non-oneworld airlines until the OP gets a satisfactory resolution to this.
I sympathise with the problem as my daughter is disabled.
OP has been clear from the outset that she wasn't being unreasonable and just wanted an apology and to be treated with respect. That is clearly beyond BA and frankly, they don't deserve my custom.
It would be nice if others did this if we could quantify the financial impact on BA. it's the only thing Walsh and Cruz seem to understand.