Mk 1 Handbrake problem - is the cable stretched?

 Another flaming handbrake problem…

After having had a very dodgy handbrake for 6 months and discovering that adjusting the nut on the handbrake lever did no good I replaced the rear discs and pads on my 1997 machine. At the same time I took the left and right cables off the car and gave them a good oiling together with the centre compensator.

I went through the usual adjustment procedure with the caliper adjuster (nipped up 'til the disc locked and backed off 1/3rd).

However I can still rotate the hubs by hand when the hand brake is fully on but infact by squeezing the actuating lever on the caliper up by hand I can get the disc to lock so I guess the calipers are OK.

Are the cables knackered (stretched) and in need of replacement? Car has done 97,000 - how long should the cables last?