Oh ok not sure what to do now. Maybe this extra info might help decide if I do have a problem. Last year I drove up to the lake district and accidentally, thanks to a sat nav issue ended up on top of a mountain. A hose blew off the radiator and I lost lots of water but thankfully I was right next to a stream so could refill and get to the camp site. I thought nothing of it at the time until now as there wasnt any reason for me to think something was that wrong. Now the fact it takes ages to warm up is something Ive not noticed before. The heaters in the car do get warm quickly though, so maybe that's an indication all is OK? But one thing I havent noticed ever before is that as soon as I start the engine, from cold, I can see the coolant being pumped into the header tank via the little tube next to the filler cap. Im not sure if this is right but to me it isnt. Makes me think that something is being bypassed or routed wrongly.
Does that point any closer to it being a dodgy thermostat or is all OK and Im just being overly paranoid after all my recent issues. Last thing I want to do is buy a new one and waste £78.