Live Songwriting - Part 1 - The Song Idea

This is something I've never done before and I don't know that I've heard of anyone else doing it either. I've always wondered how people go about writing songs and suddenly realized that this is a great opportunity to show how I go about it. There are plenty of retrospective interviews and demonstrations (not to mention analysis by experts) but here I'm going to bring you in on a song at its genesis and share the journey of creating a finished song. I don't know if it will even be completed (many don't make it) but even if it doesn't I'm sure the journey will be interesting to anyone interested in songwriting.
So today I want to let you in on the initial creative impulse that starts a song on its journey to life.
The Song Idea.
As this song reveals itself I'll use video and audio to share what unfolds but at this stage I just want to tell you about the idea.
For several years now I've been walking pretty much the same route most Sunday mornings through my suburb of Reservoir and on the main road (a fairly busy two lane road with a tram line running up the middle) is a typical 1940's style brick house with one of those slate covered low fences that runs along the front and up the sides of the property. There are a lot of these fences around our area, mostly in disrepair, but I began noticing this fence was in superb condition and usually had a small tin of mortar, a few plastic bags and a small trowel sitting on it in various locations. The rest of the house was in the normal condition of "main street houses" and looked a little tired. The garden was just functional, nothing remarkable. 
Eventually I became a bit fascinated with this fence and over time I noticed a middle aged Asian man who would be standing quite still, just looking at his fence. Sometimes he would be working on it, patiently dabbing little balls of mortar into cracks and smoothing them over. I greeted him once or twice on my way past but he never really acknowledged me so I just let him be. This has been going on for a few years now and the fence keeps being patched up and he keeps standing there looking at the fence in the morning sun. Nothing changes to the rest of the house.
So what is his story? What is it about this fence? Will it ever be finished and why not work on the rest of the house?
I often stumble on song ideas when I'm walking. I often forget them as soon as I walk back into the house as well. If I try to get them back I can only remember fragments of what seemed a fantastic idea at the time. This morning as I walked past the fence I started turning ideas over in my mind. Nothing really solid but I did develop some sort of plan. I have included a picture of one of these slate fences (not his, I think he deserves his privacy) and some notes I jotted down when I got in from my walk so as not to lose the idea.
At this point I've got nothing musically. Sometimes songs emerge from doodles on guitar but I'm beginning to realize that my better ones are conceptually fairly well developed before I go near an instrument. 
So, what is this song about? I often write songs that come into being with no clear reason for existence. They just emerge somehow and it can be really difficult trying to work out what I'm on about. These songs don't often work. Sometimes I try to get too clever by half and try to run several themes simultaneously approaching the song from too many angles. I'd have to say that these songs almost never work. The ones that work come from a simple idea or feeling. They explore that feeling (sort of living in "the now") and wrap up, hopefully making some connection with the listener along the way.
Here's what I think this song will be about. This guy is continually patching and working on his fence to a) keep busy without having to think, and b) covering over some truth that he doesn't want to see or remember. We all do this to some degree and if I get it right this song will resonate with many people. If I get it wrong it'll be some silly song about a fence.....
The next step will probably be some lyric ideas. I'll let you know when that happens.

'Wall Song' Notes

Similar pattern to the wall in the song