Hi @bko
Thank you for your reply, that would probably be what I would have to do. Could you tell me if this one would be suitable? http://www.ebay.com.au/itm/GA84705-LM385LP-1-2-Texas-Instruments-IC-V-Ref-Micropower-1-2V-To-92-/141363498199?pt=AU_B_I_Electrical_Test_Equipment&hash=item20e9ebccd7&_uhb=1
Also I was looking at a spec sheet (http://www.ti.com/lit/ds/snvs741f/snvs741f.pdf), I am very new to electronics but from what I can see you only need to connect at 500k resistor between the battery and one of the pins of the IC, one pin goes to GND and one pin is the output 1.2V. Is that right? Again as I said, I know very little about this.
Also once you have an accurate 1.2V reference you can feed it through and external AREF. Which pin would that be on the board?