right guys having a problem with the hand brake on my zaf turbo

the drivers side does what it should do

the passenger side caliper holds quite well but then will turn with a little force with the wrench, the foot brake works great, if i adjust the cable the drivers side is on all the time but no change with the p/s

ive changed the handbrake cable thinking that may have been strecthed but its still the same ive took the caliper off and wound back the piston and i can see it moving still no joy

anyone have any ideas what it might be, do you think the caliper is gone