I threaded a mains cable into my cabin from the engine bay this afternoon. I found that the metal panel behind the battery is secured with two torq bolts, one under the plastic trim under the windscreen and the other on the right by the bonnet hinge. It then comes away and revels a void with a round 50p sized rubber grommet. I found that sitting in the passenger footwell, I could thread my right hand under the dashboard, after pulling the cover under the dash off. I located the rubber grommet in the fire wall and pushed it out.
In the metal panel behind the battery, I made a 20mm hole for a plastic cable gland to protect the cable from sharp edges.
After threading the cable through, I wired in an inline RCB and an ABB make connector, which now sits infront of the battery.
I have left the cable stowed under the driver's seat for now but plan to route it under the cabin carpet to the driver's seat and wire up a single socket to allow me to plug in a multiple extension cable when static. I can also plug in the leisure battery charger when at home.
Apologies for no images.