Poor quality audio on last 2 episodes

[Mark Phillips]

I have been recording the series Petite Mort on Radio 4 - both as
individual 15 minute episodes and also as an omnibus on 4 Extra.

Episodes 1-8 and Omnibus 1 all came down at 128k AAC as expected, Episodes
9 and 10 and Omnibus part 2 have just turned up as a much less acceptable
48k.

What's going on? Anyone else experiencing the same thing with this
programme?

WM