Sooo - it's working!
Today i resoldered all the wiring; jst connectors used to make the power system a bit more modular, and also replaced the wiring loom for my buttons/li with a floppy disk ribbon cable from and old PC.
I am now running a pre-configured image from FDI for the screen - it's cured the flickering, it works 'right out the box' and it is just so bloody quick booting up!!
adding HDMI splitter and panel mount
Exposing Powerboost charging port
Insulating power, button cables and exposed boats.