thanks to those that read my post.
i followed it up by ringing pioneer directly.
2 things which i assumed was the case ;
you do need to connect the hideaway box.
power supply to the hidaway box has a constant power (yellow and 2 black) and 2 earth wires. and 2 centre output wires which are irrelevent in my case.
the power supply lead had been extended. the mistake i made was that i assumed the red is constant and black is earth.(as it was a second hand unit) the moron who installed it in my friends car extended the wires but didnt follow suit. he used the black wire as power and red as earth. it was all taped up with electrical tape so i couldnt see what was going on. i should have untaped it and double checked.
Lesson learnt here...no matter what install you do, especially if its second hand dont assume, make sure you check all wires from the source before connecting.