I've parked in the long stay at Didcot station a few times recently. It works well enough, but in common with the Oxford park and ride car parks, and many others, the payment mechanism feels clunky.
First time in, you fire up your phone, bash in a long series of numbers to give it your registration and card details, and pay. Second time, I think they're slightly too paranoid - they remember the location and car (good) but want the last three digits off the stored card (sigh).
What really grinds my gears, however, is that all these car parks have enforcement based on ANPR. So why can't I go to a website, bash in my car's registration number, my card details and my mobile phone number, and tick a box saying "charge me and text me whenever I park at one of your sites". No faffing around on the day, just turn up and park.
It couldn't be because that would eliminate a revenue stream from mistakes and over-payment based on guesses about return times ... now could it?