As promised here's the wiring diagram ( a little confusing but it's as simple as I could make it look)



Click the image to see full size.

I'll try and explain it.

The 5 pin relay is fed permanent fused power to pin 30 and when the Ignition is switched on the relay switches to pin 87 activating the 2 timer relays which only power up for 12 seconds before switching off and when the ignition is switched off the 5 pin relay switches back to pin 87a which fires the timer relays up again for 12 seconds before they shut off again.

The timer relays when triggered one feeds earths to the DPDT relay but each side of the switch at opposite sides and the other timer feeds the power (12v) to the DPDT relay each side of the switch again at opposite sides this allows the switching of the polarity down the 2 wires.

The DPDT relay when not being switched by the switched ignition it feeds the positive and earth to the mirrors one way round for just 12 seconds ( fed by the timer relays) folding them IN then when the Ignition is switched on it activates/switches the DPDT relay and this then feeds the power and earth the other way round to the mirrors folding them OUT

Best part is as the timer relays only feed power and earth through the DPDT relay to the mirrors for 12 seconds then the wires have nothing fed through them till the timer relays are next powered up, so the switch inside the car the can still be used to manually fold/unfold the mirrors and there is no back feed issues.