NJ
I have been in that position several times and that is exactly what I did on each occasion. Fortunately, I am 5'10" and weigh around 15 stone and have an evil look, when I'm not smiling. I was also known as a S.O.B. (stubborn old barsteward).
Unfortunately, you are also under pressure from your employers who want to know why you are not moving. By not moving you cannot be on time causing lost mileage. Lost mileage means lost money and quite horrendous fines from the Transport Authority and appealing against the fines almost impossible. Poor timetable keeping can lose you the route and affect future tenders.
Unfortunately, "first come, first served" is an unofficial policy for most Bus Company's.
I shall be interested in the results at the Court of Appeal and hope all results are in favour of the disabled users of public transport. I think this has been 'brewing' for some considerable time. We used to discuss this on many occasion in canteens/workplaces and especially on our regular BTEC courses.