Radiator fan constantly running any one had this problem.

[2015 Z Force 800 53/Trail EPS]

In what machine and what year? Bad fan switch or temp switch depending on the year and model.

2012 model RS6 have ordered a new thermo switch but I believe there is a fan relay located somewhere.

[2015 Z Force 800 53/Trail EPS]

Well we don't have those here in the US...I think they were called Quadzilla RS6. They are about the same as the old CForce 600s...and They had thermoswitches or fan switches on the radiator. Pull the connector to it and if the fan shuts off, replace the thermoswitch.
Here is a link to my copy of the service manual to the old CF600. It may be of help to you. This link will expire in 48 hours so..download it fast.:

https://acrobat.adobe.com/id/urn:aaid:sc:US:6b5b990a-00ca-4d22-bb0d-9628ffedc7fb

Yes there is a thermo switch on the radiator when you switch on the ignition the fan stays on even when cold the fan runs constantly if you pull off the wires the fan stops have just ordered a new thermo switch so will try that first many thanks much appreciated

[2015 Z Force 800 53/Trail EPS]

Welcome. When done make sure the coolant is topped-off all the way to the very top...no air gap.