Fill your boots Warder - happy my mods are of some use / inspiration to you.
I've actually added to it recently in the form of - an old lurpak tub, my old android phone in a water resistant gorilla glass case, black paint, and some old scraps of wood.
My phone has MX Mariner loaded on it as offline marine navigation works well with the phones GPS.
I wired in a cigarette lighter socket to the battery box to charge my phone / VHF etc.
I've fitted a rectifier to my Tohatsu 20hp outboard to charge the 7ah battery as I go so I'm off grid suffiecent.
Cheap as chip and does the job