So I get to Bath this morning on my usual commute from Reading, and hand in my advance single tickets on exiting the station (manned gate, not barrier). I'm on way back to Reading this evening and the conductor comes down the carriage asking for tickets. I get them out of my wallet - ah, they're for Didcot to Bath, not Bath to Didcot. I'd handed in the wrong ones this morning

I show the conductor my incorrect tickets, and also the correct standard return for the Didcot to Reading bit of my journey (a lot cheaper that way as you probably know). I explain what I've done, and admit it doesn't sound particularly convincing.
However, either he's had a good day, or he's a very good judge of character

. Either way, he stamps my tickets and moves on.
So heartfelt thanks to the conductor, and I hope he reads this so he doesn't have any doubt over whether he made the right decision.
John