Space was redundant anyway as HU has satnav, digital tv, reversing camera, bluetooth and the kitchen sink :-)
I took the screen out the satnav unit, cut the whole a bit wider and mounted an iphone holder in the space, ran a charger up the back and job done.
I stream the music from the phone over the bluetooth and usually have a speedo app running on the phone as well.
Only issue is that the A2DP is crap on the iphone so I can only play and pause the music from the HU but found a little program on the appstore that gets round it, kind off LOL