Firstly I would suggest you complain to the Independent Assessor, whilst he cannot change the decision of the OSC he can comment on other aspects such as Maladministration.
The next step, in my opinion is to complain directly to Ofcom in regard to the apparent lack of 'independence' of the OSC and the implications that the OSC appear to be 'passing off' offering a service that clearly does not exist, alternative dispute resolutions are required to be transparent and above all open and honest as well as being required to qualify and explain the decisions made and supply any evidence referred to as being used in their process, my experience of the OSC certainly denies this, decisions made in the OSC review were later changed or removed with no explanation offered and no attempt at rectification made.
I supplied Mark with a copy of the review by the Independent Assessor in my case, quite frankly, this beggars belief.
My complaint to the Parliamentary & Health Service Ombudsman (PHSO) is now in its final stages and likewise I intend to publish the eventual findings and hope others can benefit from my experiences.
In conclusion of this posting, in my opinion the OSC are not in a position to deal in any way with the complaint that BT are guilty of Maladministration, misdirection and telling lies rather than attempting to address serious complaints, this is true throughout the so called management of BT. I found that the OSC were as guilty as BT in every respect, confirmed by the Independent Assessor. I was lied to and had "false and misleading assertions" used in the so called final review, having complained to the senior management of the OSC they respond out of time and are not capable of answering emails or correspondence either completely or at all.
I asked Mark to let you have my contact details so that we might be able to exchange details of what has happened to us both and generally compare notes, I trust you still have my details from Mark.