Rob
Ansys Employee

OK. I think you're suffering from the inflation layer(s) squashing the core mesh (inlet tubes) and the way Ansys Meshing treats inflation when joining volumes with a large angle between the inflated surfaces.   There's a fairly easy fix, which requires all volumes to be merged, then split the complex bit out as one zone, and the sweepable zones separately. Then use sequential meshing to mesh the middle first. Have a look at the meshing tutorials and Learning videos (icon to top left of this page). 

Because of the rules Ansys staff operate under I'm not able to give a detailed explanation, however others in the community aren't operating under the same restrictions.