The lost art of calculating refunds

So a few months ago I went to visit pleaseremove in Cornwall for the weekend. I took the train - normally it's a fairly civilised journey and it's by far the most sensible option for a weekend trip to his - but this time there was more fail than usual...

boggyb 15:26: My train from Westbury is cancelled [due to a fire alarm in the signalling centre] - new eta 1944
pleaseremove 15:28: nice
boggyb 15:30: On the plus side, yay delay repay
pleaseremove 15:32: lol. i assume it isn't a real issue if they have an "upto 20mins". aka, if you know that, why not let them just stay
boggyb 15:33: Will let you know if I see smoke
boggyb 15:47: New eta 1928
pleaseremove 15:48: roger
boggyb 17:21: Am at Bristol Temple meads. New eta 1944
pleaseremove 17:25: k

Ultimately I was delayed 1 hour and 8 minutes, which fits into the "50% refund of a return ticket" delay repay category. I stuck a claim in because why not, and it was approved! GWR awarded me £8.43... for a 15-29 minute delay. Um.

There was a handy appeal button, so I clicked it and put in an appeal pointing out that I was delayed over an hour and giving my actual journey and reason for route ("the WSB to PLY train was cancelled and the National Rail app showed this alternative"). Squeezing all that into the tiny 250-character "Additional Appeal Details" box was a challenge but I managed to fit my actual journey in there as well.

And after waiting a week... my appeal was successful! They awarded me a full refund for a delay of 120 minutes or more. Err.

Because I'm me, I emailed GWR pointing out their mistake (and taking advantage of an email letting me type more than 250 characters).

That was over two months ago, and I got absolutely no response to the email. So... thanks for the unexpected 100% refund?