"Her application was refused in June on the grounds she did not provide sufficient evidence, but she had asked for an administrative review of the decision and had a certificate of application (CoA) from the Home Office. It states “you can work in the UK until you receive a decision on your application to the EU settlement scheme”."
"The Border Force refused entry on the grounds that her “application for EUSS [EU settlement scheme] has been refused” [...]"
Could be just overlapping on the timing, that she got the decision in her post box in the UK, while she was abroad in Spain. Would be the simplest explanation for the situation.
It would also allow to do a small afternoon tour, e.g. jumping on the bike and going 200-300 km through nature just to chill, and then back home. Right now this means a 1 min break at a petrol station, as commonly after 200-250 km you have to refill.
With battery bikes and data sheet ranges of 'up to' 180 km, with 70 kg passenger at constant 45 km/h, you probably get to 20% charge after 80 km already to recharge to 80% within an hour. So after an hour waiting you just get enough to barely make it back home.
As you say, with hydrogen it would allow for shorter breaks, enabling to do a small afternoon tour at all. And I'm not that stingy about a 1min or 5min break to refill.