Ok so my master cylinder cap as the test button and there are 3 wires, im taking it that the brown and yellow wire is the float light and test light and the solid brown is the earth but what does the brown and green wire do?

Not sure what MC you have, but if it's a standard Ford one as mine is, then there are 2 of the spades connected together (you can see it through the lid) and the othe is seperate. I have just about finished the wiring loom on my Locost and have a Ford MC, If you have one of those I can send ypou a wiring diagram for it if you like. IM me if you want me to.

JB

Standard sierra mc