Just incase anyone was wondering, i've recently pulled out my dash/pedal box and ran into some problems with vacuum lines behind the dash.
I had a thin black vac line that ran from the drivers side kick panel, across the top of the pedal box and thats where mine finished. Turns out it connects to ANOTHER black vacuum line just behind the right hand side of the heaterbox (I had to dig the line out and hold it witha pair of pliers to reconnect the two)
Thats one solved..
The other vacuum line (a thicker one) was indeed for the cruse module and it drops down behind the dash from under the windscreen and then connects to the vacuum swithces on the pedal box (switch(s) if you have a clutch pedal.)
So thats my vacuum line adventure so far.