Ground would make sense, wouldn't it?
As you may be able to tell, I was a little bit tired when I posted this last night!
I'd been reading this:
By applying a voltage to the CONTROL VOLTAGE input, pin 5, you can alter the timing characteristics of the device. In the astable mode, the control voltage can be varied from 1.7 V to the power supply voltage, producing an output frequency which can be higher or lower than the frequency set by the R1, R2, C timing network.
and figured it'd work.
I might just experiment with a control voltage as-is, see what happens.
Below is the schematic for it (Minus a few teeny changes that don't make a difference), nicked from the Maplin site.
Maybe I'll stick a video up (Of this and the other stuff I've built) soon.
Further question: Could anybody suggest a simple circuit to build in order to experiment with the output?