Further comment about this can be found on the BA forum here:

http://flyertalk.com/forum/showthread.php?t=680982

This thread includes links to previously posted opinions and more information about the new policy.

Whatever the Customer Services Representative's brief was regarding this, I am sorry you and your wife received such short shrift and were not dealt with more sensitively. As I am able to walk myself (albeit painfully, and under strict instructions not to walk more than 50metres a day due to a slipped disc) I also would have found myself in the same situation.

Sounds to me that the only way around a decision like this is to exagerate a condition and lie about capacity for mobility. But it's sad and unfair that BA would force their passengers to lie like this, compounding what is already a stressful situation.