If you create a package and use the "Advanced Tab > Package Destination location on package servers (leave blank for default:" option, specifying a UNC location, the Package Server on the Parent/Child NS, Child NS, as well as the Child's Package Servers will fail to download this package.
This is because the Parent/Child NS downloads the package and then moves its files, as per the Packager Server setting. This is OK in an NS to PS world, but produces problems in an NS to NS world which is three or more tiers deep.
As the contents of the cache directory have been moved, and the cache directory itself has been deleted, when the Parent/Child NS runs its Package Refresh or its Update Distribution Point actions, it fails to do so for these types of packages because there is no cache directory.
The attached is a WiseScript tool that contains a VBS file created by Chris Moore and Richard Taylor based on my requirements. It copies the files back into the cache directory from the location that they have been moved to.