what's a good value for a used Sony Z1?(UK)
 

I am seeing a few around for more than £2,000 which seems a lot to me...

some of these camcorder show quite a lot of hours as well..

can anyone help me understand which one of the parameters I need to look more at when judging a used camera (normally the Z1 gives you a screenshot indicating
1) drum run
2) tape run
3) threading
4) operation

etc etc
what would you consider an acceptable limit for these parameters? (sort of like buying a used car)