Ok, the current solution is this...

One of these in each robot so I have a 15V output from the weapon system...
http://uk.rs-online.com/web/p/switch...ators/0416846/
...then an in-line resistor to bring the voltage down to 12V.

Since I need 260mA of power to drive the LED's in Conker 3 I need a 12Ohm 2W resistor (15V Source Voltage, 12V LED Drop and 260mA current required to power all the LED's).

In Binky I will need 120mA of power so I will need a 27ohm 1W resistor (15V Source Voltage, 12V LED Drop and 120mA current required to power all the LED's)

Can anyone see an issue with that plan?