Llanrads Hi! nice to hear from you!
Last night I replaced my Stat.
Temp gauge would read just above 50 when driving.
to further diagnose I connected it to FES and monitored it when stationary - readings on temp gauge were pretty close to what the ECU was telling me - while stationary it climbed to 90 and then fans came on.
Also I noticed heater always pumps out really hot air even though dial is way over to cold setting (not sure if this is related??)
For me that was enough evidence to change the stat.
I covered the bell housing with some plastic sheet, which directed the spills into a bowl.(I've only just changed coolant so wanted to keep it!)
Took the two bolts out to dump some coolant and allow the stat to be rotated to access the lower clips.
BTW...there are two types of clips, one type (like the ones on the air duct) are re-useable and easy to open/close with one of these pliers
Draper 89791 Clic and Clic-R Hose Clamp Pliers: Amazon.co.uk: DIY & Tools
The second type (like a metal cable tie ratchet principle) looked like a 1 time use only to me? so I replaced just those ones with good quality stainless jubilee clips.
Job took about 1 hour with a few skinned knuckles. Stat cost £33 from a local motor factor.
Old stat was original (1998) and whilst it appeared to be closed, I could blow past it slightly.
Missus has taken the car to work this morning so I'll get a report later no doubt!