As nobody replied
I plugged away on my own and made some progress.
I am running HFS on a Windows Server 2008 R2 server and what I did was create a real folder called Uploads and a virtual copy of that called Downloads. I did this by right clicking on the real folder name and copying it to a virtual folder which gave me Uploads (1). I then renamed that virtual folder to Downloads.
I specified no uploads to the virtual Downloads folder but with no restrictions on access which gave me the situation I wanted where only specified people could upload to the real Uploads folder provided they had the necessary credentials but anybody could download from its virtual clone, the Downloads folder.
So far, so good.
I could see the folders and their underlying structures. Each of them reported the sub folders of /documents, /forms and /pictures and both folders showed the same content.
Again, so far, so good.
I then used the template to visit the two folders using the URLs
http://99.999.999.99.1000/Uploads/Forms and
http://99.999.999.99.1000/Downloads/Forms and the Uploads folder correctly asked for credentials and the Downloads one didn't.
I used the template to upload a file to Uploads/Documents and it did it.
By now I am feeling really good (and a little smug.)
I should have known better because while I can see the uploaded file in the Uploads/Documents folder the Downloads/Documents folder shows no content. I seem somehow to have updated the real folder Uploads/Documents without updating its virtual clone Downloads/Documents and I can't for the life of me work out how I could have done that. It's clearly something to do with permissions and folder rights/properties but I can't find these. Logging in to HFS (by clicking the Login button) makes no difference.
On top of this when I log onto the server via Remote Desktop and go to the HFS screen I can no longer see the sub-folders; ie I can't expand the two folders Uploads and Downloads.
So I have 2 problems; how can I somehow differentially update a real folder and its virtual copy/clone and why can't I expand the folders I created and can see in the HFS left hand window so I can check their contents?
I am so near to getting the HFS configuration and functionality I want and it's so frustrating but, hopefully, someone can tell me what I am doing wrong?