After washing the car today I started to nose around a bit more for an easy way of routing my 12 power cable for my ice install. Not sure if this has been posted before, but heres my solution. At the rear of the engine bay, attached to the firewall, you should see a thick wedge of cables entering a large pretty solid looking grommet. The cable can be passed through here with ery little effort and fished out from behind the dash after feeding enough in. Needless to say the photo isnt brilliant, but I'll do a full write up of my findings in future. ...and yes that is a length of mains flex