I had problems with the code on my radio & was looking at a new head unit ( code now resolved so didnt need the head unit)
As far as i know the P38 radios n cds are all clarion- so get the model number off the changer & look up what head units are compatable.
I was told by a radio engineer type blocke that Land rover charge about £600 for new unit WOW!!!
But try scrappies or good old ebay as i found a few on there going aroune 60-100 quid. Make sure they know the radio code or like me you'll end up spending min £20 getting it uncoded.
good luck