I managed to find the video. It's quite a frustrating watch, with endless histrionics and weeping, as well as some very put-upon station staff. The TM doesn't make too much of an appearance, but more on her later:
A number of things spring to mind:
1) I've come across this woman before - likely on this site, from a previous incident?
2) It seems the only issue was that the TM was someone that "Agony Autie" complained about before and this is the reason she was denied travel. The TM seems to suggest that the complainant has been abusive to her in the past. In the video, the complainant asserts that the TM "was disciplined". I used to work for Virgin in their complaints team and can categorically say that at no point would the internal outcome or any disciplinary following any complaint be made known to a complainant. This does not happen.
3) The complainant is a very difficult and unpleasant person who cannot manage conflict. The complainant does literally nothing to assist in any de-escalation, becomes needlessly hysterical, etc etc. This is likely at least in part due to her autism.
4) I feel sorry for the station staff who were put in a very awkward position.
5) Regardless of whether the complainant is or is not a difficult person, I feel sure she has been treated less fairly than someone without a disability. None of us can say whether or not she has been abusive in the past. This notwithstanding, had she been able-bodied, she would have simply got on the train without fuss and the TM likely unaware of their presence.
6) I feel this incident raises issues surrounding the concept "it's the guard's train, whatever they say goes" - yes, but up to a point.
7) I don't get why the TM felt so unable to convey the complainant one stop to Chester, a journey of what, 20-25 minutes?
8) The whole situation seems to stem mostly from the TM exercising unnecessary power over the complainant, when it would seem easier to just let them travel.
9) I believe this is the train:
http://www.realtimetrains.co.uk/train/Y81538/2019/05/17/advanced - it accrued a 22 minute delay at Crewe solely due to this incident, and ended 28 late at destination. That's disruption for hundreds of people on the train and failed PPM with associated performance penalty for the TOC.
10) The TM was allegedly calling the police on the complainant at the time the video was shot. It is not clear exactly why, but it cannot have been for something terribly serious as other staff intervened and treated her with quite a lot of respect given the circumstances.
The TM should have just let the complainant travel. Nobody comes out of this looking good, but I wouldn't like to be Virgin defending a discrimination claim here!