Further to my first message, I installed HD Sentinel and it gives the following info about the interface:
Hard Disk Summary
Hard Disk Number,6
Interface,SAT Standard USB/ATA
Vendor Information,"VID: 152D, PID: 0539"
Disk Controller,"Renesas Electronics USB 3.0 Host Controller (USB 3.0) [VEN: 1912, DEV: 0015] Version: 3.0.23.0, 8-21-2012"