Hi thanks for the reply. It doesn't have A/C and no electric fan, however I will include the fan clutch in areas to investigate.
Checked it today and the coolant level has gone down slightly, leading me to think either there is a small leak I can't see or an air pocket in the system. I might try the bleed procedure but I'm still baffled why it would suddenly need bleeding after 3 years of driving. Other than that I'm just gonna have to take it easy and keep a close eye on the temp.