Just ordered a new OEM coolant temp sensor and a multimeter, sending back the Tridon brand one...hope this gives me a result. Will look into a aftermarket gauge to cross check just incase, well worth it to prevent engine overheating!
Edit: If interested, $32 posted here, about $20 less than Kudos
https://goodstate.com.au/index.php?route=product/product&product_id=w192561392204