I've been recording these programs on BBC4HD by setting each one individually rather than a series link. Before Wednesday and Thursday last week all was ok but then..
Two recordings at the end of last week both had Audio Descriptions turned on by default when I started playing them back - I've never had this feature switched on before and it's never happened before. I got rid of it by toggling this setting on and then off again for each recording during playback.
Then last night the recording of the program at 7pm recorded 6 seconds and that was it. There was no error code with it.
So I set a recording of the repeat of this program in the early morning and this didn't record at all and had an error code of R120 when I looked in the recording hiccups.