OK, here's the situation:
All parts of a post have downloaded but some are marked as being incomplete.
All PARS have also been downloaded and one is marked as being incomplete.
THEN nothing more appears to be going on (left for 15 mins)
I then highlight all the broken RARs and tell newsbin to create them anyway
The new RARs are then marked as being in need of repair.
I leave it then for 15 mins and newsbin appears to be stuck again, so I have to manually tell the broken RAR to be created anyway.
THEN newsbin becomes active again and starts to download more PARs and then creates the complete MKV.
Similar to the poster of this message, I am wondering if there is something in the settings that I have overlooked to get newsbin to download incompletes if there are enough PARs to cover the deficit.