May have just realized the issue, I hope :)
The controller to drive cable (no HD backplain, direct to drives) I have is;
"The SAS8087S4R50 SFF-8087 to 4x SATA Reverse cable features one 36-pin plug (SFF-8087),
which fans out to four SATA 7-pin receptacles, providing a reliable solution for
connecting a Mini SAS backplane to a SAS / SATA RAID controller or motherboard."
* Good thing I found the bag with the model # etc...!
This sounds like maybe the ~correct~ cable;
"The SAS8087S450 SFF-8087 to 4x SATA SAS cable features one 36-pin plug (SFF-8087),
which fans out to four SATA 7-pin receptacles, providing a reliable solution for connecting
up to four SATA HDDs to a SAS controlleror backplane."
Does this sound about right?