Cable route from battery to dash

On my to-do list for the weekend - wire in an aux fuse box.

My intention is to take a live feed straight from the battery to behind the dash, where I'll stow an aux fuse box accessed from the panel on the passenger's side. I can then use this for permanently live feeds or tap a switched wire and use a relay, depending on what I need.

What is the easiest way to route the supply from the battery box?? Out and along the chassis and back in through the bulkhead? I had thought about trying to run it under the trim along the side of the tunnel, but after realising how warm this seems to get, I'm not sure this is the best bet!

Cheers

I ran the supply to my aux fuse box from the big terminal on the starter motor. It enters the bulkhead through an existing cable grommet on the passenger side of the bulkhead, near where the wiper motor lives. The wire is then tucked behind the dash tray to the rear of what used to be the 6 way light switch in the centre of the dash (my 90 is ex mod).
Not sure what the access to the bulk head is like on the TDCi but I would imagine you could apply a similar principal??
TBF I would have thought that the cable would be fine if you ran it under the trim by the tunnel. For added protection you could use flexible plastic trunking or even a piece of hose pipe.

Rich

Spent the afternoon pottering about with various bits and bobs, decided fitting the aux fuse box on the bulkhead behind the passenger's seat was the easiest option for install + most useful for me long term.