Uh oh OS booting starting to take noticeably longer, getting some intermittent read errors and its noticeably struggling with some test files I've been keeping an eye on (some of the oldest files written to the disc). Guess I'm gonna be forced to replace it if the update doesn't do anything - if I'm gonna be messing about with a secure erase and setting up the OS again, etc. I might as well bin it and replace with a drive I've better experience of the reliability of.