It's in the passenger side foot-well area. On the right hand side of the footwell area you'll see a grey panel with two caps that pull off. Take them off and you'll find 2 plastic screws, remove them and the cover should come off. It's handy to take the glovebox out and unclip the fusebox from it's bracket and take the bracket off aswell but I've heard of people doing it without all that before..
The filters actually located in a black rectangle shaple box, with about 4 screws holding the cover on.
the bluetooth on my phone is always on - so I will try turning on the headunit and then starting the car. Hopefully if that works I can then just turn on the stereo everytime I enter the car before actually starting it.
Fingers crossed. Thanks for the help, I'll update you to let you know how it went.