I presume you checked getFileSystem worked on the DiscoveryAccess from the scan. If that does then you are really going to have to raise a support case because it is going to be very difficult to investigate on the forum.
Hi Andrew, someone had made changes to the platform script and this impacted all hosts. We were not aware of the change and assumed the issue lied beyond this point. Unfortunately it was the last place I checked, but there was no reason to believe it had been changed. Good reminder to go back to the basics when troubleshooting. Thanks for the response!