I am very sorry to read this set of events, which serves to highlight what a bad deal, verging on discrimination, that the disabled often get. Of course it was basic incompetence (rather than active discrimination) by the agency employed by Heathrow Airport Limited, formerly known as BAA, and that agency is Omniserv. Their email address is here:

[email protected]

I would urge you to pursue the matter with both the airline and Omniserv. BA typically spends several months before replying to customer service issues, unfortunately, and depending on the answer it may be worth coming back here for further advice on escalation if necessary. I suspect the Omniserv response may be faster. Clearly they can't repair the damage, that has been done, I would hope you could embarrass the agency into avoiding this in the future.

You do have some other options open to you, in terms of media exposure (there is a very good radio programme on Radio 4 which may look into this); also I have a feeling you could claim for Involuntary Denied Boarding, see the EU261 thread elsewhere in this forum. BA would probably feel a bit hard done by if you went down this route since they neither employ nor regulate the agency concerned and the case would therefore fail due to the fact it was largely outside their control. I presume that the "desk" you referred to was in the Galleries Club South lounge so BA can't completely escape some responsibility. But it would mean that the issue would be highlighted.

And I hope you will consider taking the matter further, since it's not good enough, in 2014, for those with disability to be left in a corner and ignored.