heater problem octavia 1.9tdi

Hi Guy's

I've recently been having problems with my blowers on my Octavia 1.9Tdi.

Basically, they are not blowing very warm air through to the car and i've also noticed that the engine temp gauge does not move very far. Even after a long run, the engine is only luke warm which makes me think that the stat may be stuck open allowing the water to circulate continuously.

I'm no expert with car's but i'm wondering where the stat is housed and if it's simple enough to change before i may have to take it to the garage.

Thanks Guy's