I should have quoted someone - it was for Lord Grievous who said:

Sigh, it still has the same problem. It plays fine on the PC and MediaInfo says the remuxed sample plays at 23.967p, but on my telly it's still sped up and no sound.

Remuxing to a .mkv without reencoding the audio should work in this case. For whatever reason there's something wrong with the container, or the TV's reading of it (I also have a Samsung TV and had this problem) which is causing the audio to go unplayed.

I didn't have to reencode either the audio or the video from my problematic .m2ts - I just had to put them both in a .mkv container and all was fixed.