Ewan
First your picture doesn't open for me, best load some pictures in an album, just go to Albums in the top menu bar.
Value will depend on mechanical condition as well as electrical/electronic functions working. If it is in good sound condition and a later model with M codes in addition to G codes it is a useful machine as is.
If fitted with the auto 6 tool turret it will attract a much better price.
If it is an early Mk2 machine it will be worth much less and probably ready for a refit with modern steppers and controls, check the G codes listed on the control panel and note any M codes listed.
You say the Z axis is not working but the X axis is, perhaps if stored in a outside location it could be corrosion on the stepper supply plug/skt at the back of the machine, try removing and re-fitting the Z axis plug a few times, use some contact cleaner if you have some.
Switching the Z axis plug to the X axis outlet would check if the Z stepper control has failed but it has risks because if the Z stepper motor has short circuits between coils or frame the X axis driver could be damaged.
With an ohm meter you can check the resistance values of the stepper coils, if you want to do this I can provide the expected values of and between coils.
Emgee
Edited By Emgee on 10/06/2021 20:17:48