One thing that confuses me, is the old app and website were visibly Trainline, while this looks nothing like other SilverRail-based apps. Did they purposefully take a backed-only service from SilverRail and develop the frontend in-house (or had a cheaper third party do it), or does SilverRail only do backend anyway?
I suppose if they got a cheap contractor from abroad for the frontend, with no experience of UK railways at all, that would sort of explain the unacceptable intended UX. The abysmal quality is another thing entirely.