Engine idle / Viscous fan problems

Hi, I’m a newbie to forum so forgive if not posted in correct place. I have a L322 2006 HSE Jaguar engine Range Rover. Recently installed a FSR following hvac problems. Local Range Rover advised to disconnect the battery for 24hrs to clear obd errors as diagnostics wasn’t clearing error.Problem is that when connected the engine fan now comes on full belt in park and idle speed revs up to approx 1100 rpm, it also threw up an error of low coolant which wasn’t low. Knowing that it could be viscosity of the antifreeze I flushed and replaced which cleared the low coolant error with diagnostics but not the fan/ idle issues.
Diagnostics now shows a P0626 and battery icon on. Battery is 9mnths old and tested 12.4volts.
I’ve now after disconnecting battery following visit to RR garage got something that sounds like a tractor and their response is “bring it in and we’ll charge you to connect to our diagnostic before looking at problem” I’m using GAP iid bluetooth Diagnostic.
Any help would be appreciated

Oh Sorry forgot to introduce myself. Stew from Northumberland.

Welcome to the forum

This ere section is for introductions only. Yer be betterer to post questions asking for help int range rover section. Just be careful in there. They're all nutters.