Its just flattening my battery and leaving car headlights on? Even used ISO an adapter. Stereo is staying on when I have ignition off. Can someone tell me how to do this as don't really fancy paying £30 at Halfords to fit the radio!!
I'm not sure what your headlights have to do with an audio system? If you are fitting the audio system yourself, you need to find a switched source of power, one which comes on when you turn the key. The best way to fit this is to buy the adapter kit for it, which will give you a wired adapter which plugs into your car and aligns with the color coding on your radio wiring. This will get you your switched power lead.
Take a look at this image.
What I'm talking about is the adapter portion which is hanging down. I have no clue what this one is for, but you should have on similar. If you do have one and the end is attached to the car plug, I'd look to see to make sure the wires are aligned correctly. The main power in for your Peugeot should be switched, so the correct adapter will associate this power lead to your head unit.