As its been asked before many times how to run live from the battery to the cabin can i suggest a sticky for this.
Mini How To:
Open to Glove box on the drivers side,
Squeeze the sides of the box to release the side guides that keep the box in place.
Box will drop down unclip it from the hinges.
Using a flat screw driver and turn the 4 plastic retaining screws 90 degrees.
Open bonnet and locate grommet between bonnet release cable and master brake cylender.
From with in the car push this grommet out using a long knife / screwdriver. (i used a knife so i could retreave the gromment from the bonnet side.
Run the power lead from the battery (not connected) and secure to the sleave of the bonnet release cable.
Feed the leed through the hole where the grommet was.
Make a hole in the grommet using a sharp knife / drill (slowly)
Slide the grommet over the power lead from inside the car,
Pull through any loose cable and replace grommet back in hole.
On the far right side of the dash you can feed the cable down into the side kick panel.
Using a small flat screw driver remove screw cap on kick pod and using a torx driver remove the screw.
Push the rubber door seal off the pod and push pod gently towards the centre consol (do not remove it or snap bonnet release).
Pull cable through the gap.
push side sill covers towards the centre of the car to release the clips, do not try to remove them just make enough room to feed the cable in.
Lift the base of the rear seats and feed the cable under the end of the plastic sill cover.
Replace trim by sitting outside the car and pulling towards yourself, becarefull to lift the rubber seal as you work your way along.