So, today's update is titled "well that didn't work" as I made a few mistakes I need to correct.

 I think it's important to show the process of building so people see it takes time, and that we don't just go from idea in our heads to a working product in one easy step.

So the first issue I have is that I started soldering the power wiring into place.
  

The eagle-eyed among you will notice that the BATT input is wired the wrong way round. This is due to my battery using reversed colours, something I didn't know until I tried plugging it in.

The battery still works fine; this one section just has the wrong colours.

The second issue revolves around my battery charger and DC step-up converter.
My charger can only output around 4.2 volts at 1 amp, so my intention was to use a DC-DC step-up converter to make this a stable 5 volts. However, this little PCB 
 
 It can only output about 480mA max at 5 volts, so it is completely useless and has been removed from the parts list. I had far too many tabs open with DC-to-DC converters, and it seems I purchased the wrong one/ got the data sheets mixed up.

So what are the next steps : 

The wiring with the wrong colours, I'm just stuck with, so that is what it is. 

The power converters I have three open 

1. Find a new step-up converter that can do 1 amp 
2. Find a new battery charger that can output 5 volts at 1 amp 
3. Run the pi directly off the battery at 4.2 volts ( not recommended) 

I will be exploring these options over the next few days.