Well.... The head unit turned up this morning... Well packed, No additional costs.
I also installed it today all went well took me about 2hrs, I noticed whilst fitting that there was a 3.5mm input and output cable within the loom... I feared this might be the case.
Upon testing I discovered that the audio output was / is very low... when playing music or youtube through the head unit To the point that I have to have it turned up to flat out and its still not loud enough.... If I switch over to the radio within the OEM unit its double the volume...
I'm guessing that I'm going to need some sort of inline amplifier to increase the volume.
Had I known this before buying I seriously would have had to have good think if I wanted it or not.