BA continues to fail to handle this situation properly and you are right to feel aggrieved. The CAA in the UK has now taken over from the Air Transport Users Council as the appropriate body to help you. Send them your detailed complaint... I wish you well. Here are the contact details...
Write to:
Complaints
Civil Aviation Authority
Room K401
CAA House
45-59 Kingsway
London
WC2B 6TE
Phone:*******020 7240 6061 (Advice line Mon to Thurs 9.30am to 2.30pm)
Fax:********** 020 7240 7071
Email:
passengercomplaints@caa.co.uk
I think you will be successful, but it is shaming to have British Airways behave like Delta... They are a disgrace.