Hi Matt,
Yes, that's what I want to do.
As the archive will be static I'm not looking to manage it as such and may well opt to store it all as Standard Infrequent Access. It isn't intended that multiple users will be accessing the archive either, just the central PACS application servicing clinician requests. Because of this, I don't think the Explorer product is applicable. I'm not sure I understand what your caveat is, but I think, for the server licence cost, I'll try it and if it doesn't work out will use AWS Storage Gateway.
Thanks for your quick responses guys!

I'm sorry Anton, but I think we are talking at cross purposes. From what I can see, Ultimate is a backup solution. I am moving the data from a system that is going to be retired into the cloud (S3) and want to be able to access it in a transparent way from Windows Server. The data will be static and I don't want a backup solution. There is a Cloudberry drive for Windows Server and this looked like a viable solution...but you are saying it isn't dependable?

Thanks Anton, the reason I'm looking at Cloudberry drive is on understanding that there isn't native support on Windows box to link to S3. Is there something I've missed here? The number of requests to the archive should be quite low so should be manageable. Using block storage or other options is too expensive and hosting locally would then become viable.