Thanks, yes, i think I will buy the cable for how much they cost, not a lot.
Online advice on this is massively contradictory so a quick question guys please. My i5 based late 2013 iMac has the fusion drive. Do I need to break this drive into the two parts? What I'd really like to do is to install a new NVMe drive on the logic board and add a SSD in place of the HDD, both drives being 1TB or even 2TB. Then reboot the whole shebang with the two new internal drives to give a system with masses of solid state storage for Lightroom and Photoshop.