Salty seadog
Space Cadet...(3rd Class...)
GNOME Disks will do. Fire it up, look at the lines saying "Assessment" on the Hard Disk entries (not the Drive or Block Device) ones. It should say "Disk is OK". For extreme detail, pick the "SMART..." entry in the menu. The pop-up window may also let you run extra tests, but it will probably require you to become the root user, possibly before starting gnome-disks.
Splendid thanks. I can work my way around Windows on for the main things but Linux, not a clue really.