Cheers guys! I knew about the blue wire on the dimmer switch from a Vortex thread i read lastnight - this also means that the guage should dim with the rest of the lights when you use the dimmer switch right?
Hopefully i'll just tap into those screw terminals then. Need to pop by a Halfords on the way home to get some more vacuum line as the length that was supplied with the gauge was not long enough
For the record i have fed the vacuum line via the wing (as i do believe Rhyso has done) using the rather large grommet in the door shut just below the hinge.
