Many thanks for the comments and encouragement, I'll continue to post as much as I can here first for those interested in this project and are familiar with an arduino.
This tutorial here (
http://bildr.org/2012/03/rfp30n06le-arduino/) covers the use of a MOSFET transistor to control a light or a motor and is the circuit I use for controlling:
Front/Back Light
Left Indicator
Right Indicator
Cooling Fan
The main Motor
I basically use the same circuit * 5. If you're able to build the circuit on an arduino uno for example, as a test, you've done most of the hard work! It's important to note I've replaced the original bulbs in the lights and indicators on my C5 with low power LED bulbs to keep the power usage down.
This circuit:
http://www.arduino.cc/en/Tutorial/PushbuttonI'm using to read the left and right indicator button and also the handlebar switch input. Again this is a very simple circuit to implement.
Measuring the temperature is simple too:
http://www.youtube.com/watch?v=_fNto4JOu4EThe main problem's I've had is soldering all the above onto the circuit board at the rear of the C5 and all the wiring that then goes back to the front where the display is, and trying to keep it all as compact as possible.
The circuits above are really simple to do, and with a minimal amount of coding you can see them working. It's the arduino that does all the hard work.
As mentioned earlier in the thread I will make the source code available soon (there's a few bugs still to iron out) and if anyone wants to build their own variant of this project, and maybe add features to it such as pedelec (and maybe sell it on themselves), I have absolutely no problem with that and will help where I can.
I'll follow up later on with pictures of the LCD section and the changes I've done to that with some pictures and also pictures of the rear circuit board and wiring.
Thanks!
Dan