Archie64

HI folks, looking for a bit of help here, both of my fans stay on all of the time whilst driving- as a consequence the car takes around 30 minutes to reach working temp. I have looked through all the forum threads regarding this and it looks like the first port of call would be to replace the temp sensor - I have bought one (less than a tenner) but for the life of me I cannot see where it goes -I dont know if this is me being dumb or if it is obscured by the front cowling as I cannot actally see the rads from inside the engine bay. Can anyone take a photo or give me a link to a diagram that actually shows the location please?
My car is a 2008 A8L 4..2 petrol fsi quattro
Many thanks for any help.