A quick follow up for anyone searching on the same issue.
I was happy to find that the cable was perfectly ok, just needed a bit of a lube. I disconnected it from the throttle body end, held it straight forward and up from the firewall and shot some PTFE based lube down the cable sleeve while my helper pumped the accelerator pedal. This seemed to work the lube in nicely.
I have not yet tested it while driving, but it feels immeasurably better in the driveway.
One strange thing, at least to me, is that the cruise control appears to drive the accelerator pedal itself, rather than going directly to the throttle body like most that I have met before. Therefore I am hopeful that the cruise control will behave a bit better, it has been very poor at holding a constant speed for a while.