Connecting to a permenantly on 12volt power supply?

Hi, I'm about to install a gps tracker that requires a 'permenantly on' 12 volt power supply.

I have a Gen 1 2003 MCS Works.

I am not familiar with the MINI electrics/fusebox etc and haven't previously done any DIY work on my MINI apart from changing failed parts.

Is there a very easy and neat connection point that I can access.......I'd prefer something that I can simply plug in to, or a spare connection on the fuse box that I can access without having to cut into the existing wiring or disturb the interior trim?

Any suggestions?