I do however have a secret weapon. My digital camera. An eye that sees where my head won't reach. The other day I used it to see what lay behind some of the batteries, where I can't possibly see by normal means. There just isn't the headroom. Here we see two things hidden from my normal view, the back of the master switches and the space behind one of the batteries, showing a batten I didn't know was there.
In a boat engine bay like mine, a camera is a wonderful tool. You can peek into out of reach crevices, take a spanners eye view of an inaccessible nut and spot where bits of wire go as they disappear behind the calorifier or whatever.
Stop press. As I write this (at 10.30 am) the postman has just delivered a bus bar that I ordered off ebay at 4pm yesterday! I'm impressed. Remember the old days of "allow 28 days for delivery"?