Kioti 9010 DX PTO switch problem

[MF254]

Hi, I have an intermittent issue with the PTO switching mechanism on my Kioti. I have followed the various threads on this issue and so far have had an auto electrician check the PTO switch in the cab; check the solenoid that controls the hydraulic oil flow; had the electrician clean and check various connections; had the hydraulic experts check the operation of the hydraulic oil valve moved by the solenoid. All good but the problem persists. Sometimes the PTO just will not switch on; sometimes it will start run for a random time then stop. Sometimes although the PTO has stopped, the tractor will not restart as it 奏hinks the PTO is still on. It is frustrating and so far expensive without result and I keep losing valuable time (and bad for my reputation as a contractor).
I must be missing another link here? Is there another associated switch or relay, a safety switch. If so where? All suggestions would be greatly received, thanks.