The sleep code I have works with a jump from GRD to Pin 2.
What is jumping from ground to pin 2?
BUT it doesnt work from the PIR and I think this is because its not exactly 0v or 5v - is this the case and if so how do I fix it?
The PIR is a digital device. It outputs a signal that is HIGH or LOW. It should be connected to a digital pin. Determine whether HIGH means motion sensed or all quiet. Then, using either RISING or FALLING in the attachInterrupt() call to be notified when the device senses motion.
Any output from the device that is above 3.0V will be seen as HIGH. Anything lower will be LOW.