Thanks for the replies everyone.

It sounds like it may have been a case of autofill. Thanks for the info there - very helpful to know (for the future at least).

I didn't use any special characters. I do type Chinese and Japanese, but if I'd used autofill I'd have needed to have been on English to type 'D', and if not I would have typed my name all at once. So I don't think they're likely to have been a problem here, but it's possible.

It looks like my best case is that I should have been allowed to change the name on my ticket at the time of check-in (good thing I was there early) as I can prove I checked in within the time window allowed in the T&C.

Jesse