Is it possible that Sounds only carries Transcription Services recordings? If so then that would explain the absence of 'Dishonoured' and 'Dishonoured Again' both of which survive in their original broadcast forms.

I'm don't *think* that's the case, there are episodes on Sounds from different sources and in some cases an episode is audibly patched together from the best extant sources. I did notice this was a really good quality recording though, and that explains why!