Well spotted. That's probably a
better outcome than what might have been charged on the day if the booking office clerk had acted correctly, as there would have been a £10 change fee to pay on top of the fare differential, although:
- Had the correct information been given the passenger might have decided to not pay and wait for the later train; and
- It's possible there were advance fares still available on that train which we have no way to know.
Best advice remains to pay the £22.50.