Customer service on British trains is excellent. It only takes a few minutes to claim Delay Repay if you're delayed more than 15 minutes, and you can even set it up to do it automatically for you. If your last train back home for the night is cancelled at 1am, you can message the company on social media and they'll pay £100+ to sort you out with a taxi for a distance like London to Cambridge.

I consistently find railway workers to be some of the most helpful and approachable people I have to interact with, which is remarkable given the sort of people they have to put up with. I think the sort of person you'll be speaking to certainly depends on the part of the country you're in though - in Scotland and Wales, I've seen people who've been let off for having a ticket that expired several days prior, and staff are happy to have a friendly chat if the train isn't too busy.