Where's my thermostat?

I may be slightly thick, but I really can't find my my thermostat. I'm having similar troubles with my temp gage and fan running for a long time after it really should be. I want to check the thermostat, but after having a really thorough inspection and consulting the haynes manual, still can't find it. Does anyone have any info or pics that may help?

Thanks

It's an a3, 1.6 petrol, 2001/Y reg

Didn't even think about manual, will look asap and see if it holds the answer.

Thanks