Just catching up....so if I play the old foxsat recordings (which are now mounted in an Ubuntu machine) on the T2 (via a mapped Samba drive) I hear the AD track. So I continued my eternal googling and stumbled upon Raydon's "convert files" utility, which appears to do what I want (i.e. allow the "normal" audio track to play, rather than the AD track). The only problem is that it runs on a Foxsat, which I have now cannibalised.
If Raydon's utility can run in batch mode - i.e. if it can be invoked once to "clean up" all of the .ts files on the Foxsat disk, them I do have the option of putting the foxsat HDD back in the foxsat machine, running the utility, then re-copying all of the files. Since the file copy took almost 12 hours that's not a very appealing prospect however (and I have an increasingly impatient wife asking when she will be able to catch up with her viewing). I'm hoping I can maybe find something that I can run from the Ubuntu command line that will process all of the .ts file audio tracks in one hit....