Download is available from
http://www.hauppauge.co.uk/board/showthread.php?t=15034
Yes, fixes the audio issue. Replaying recorded TV now includes sound (even for stuff recorded previously - ie before this patch).
BUT
CPU usage still high (15 - 20% on HD preview channel)
EPG still very limited, though just now is showning up to 4 - 5 hours hence (next 4 programs on TV2).
ie. still no MHEG-5
Also, as always, applying the patch destroys existing customisations, so have to go through the process again.
Anyway, the audio fix is very welcome.