Well, that was a game-changer!
In Disk Management, I successfully manually assigned drive letters to the 2 partitions on each 3 TB drive as you suggested.
The partitions are all recognised as NTFS( they were before) but I can now explore the partitions in Disk Management (and File Explorer) and can see the data I transferred to the partitions before the re-install of WHS2011 - Hooray!
Also, I can now see the partitions in the Dashboard under Hard Drives - excellent!
So now I want to get the new empty Server Folders(there are no new backups of Client computers or anything else since the re-install) off the 250Gb System drive and onto one of the other larger drives, which I assume is simply accomplished via the "Move
the folder" command in the Dashboard?
And then I would like, if possible, somehow to amalgamate the data on the old Server Folders into the new folders in such a way that the system recognises the old Client Computer backups and would be able to access them for Restore purposes, if required.
Would that be possible?
Many thanks for your advice so far!