Not Disabled Enough, But Not Able Enough Either

Wondering why, if it is against the 'rules' to consider where I work, or the sort of work I do, when determining whether I meet the eligibility criteria for the higher rate of Mobility Allowance, the fact that I am working, and, in the course of working, cover wards in hospitals and nursing homes, has been cited as proof that I am not disabled enough?

I feel as though I am being punished for refusing to fit the stereotype of the disabled benefit scrounger. Working seems to somehow go against me. I used my DLA money to lease a car so that I could get to work and go on my rounds every day at work. Apparently the DWP would be happier offering largesse to the tune of a princely (technically 'princessly'-- just look at the gender bias inherent in the English language!) 189 pounds a month (or whatever it is...the appeal has been going on so long I don't even remember what I was getting, exactly) if I was staying indoors and out of sight.