Just took delivery of my new 2018 JCW Countryman and am looking for any learned wisdom on how and where to route a power cable from the battery compartment through the firewall and into the cabin area.

I have successfully done this on each of my prior MINI's (Gen 1 Cooper & Cooper S, Gen 1 Countryman, Gen 2 Coupe and JCW GP) to provide permanent power for 100 watt class amateur radio equipment and now need to do the same on my latest baby - hopefully with as few hand and arm abrasions as possible!

Any help/suggestions will be gratefully accepted