Why do you need a heading lock giro in a combat robot? (I can forsee blind panic when you send a turn command and the thing turns... then just sales off in a straight line in the same direction it was going before!!, been there, done that!)
All you need is a plain rate giro with an on/off switch as Ed says.
If you are feeling clever, you could make up a simple switchable signal reverser so your giro will still work correctly when your machine is upside down, (I did one for Pillow Torque using 2 giro on/off switches and 2 signal reversers)