CR213X head unit removal from plastic surround

[RCR37]

Recently purchased a ZT CDTi (56 plate). The radio code is being asked for and there is no paperwork to tell me what it is. I've seen the threads which suggest the code might be on the chassis so I've removed the unit following the forum instructions. But how do you remove all the plastic & black metal surround which comes with the CR213X head unit (silver bit)? Does it pull out from the back or from the front? The front plastic facia seems to be in two parts - does this have to be separated to remove the head unit?

I'm thinking of replacing this head unit with something more modern - but I want the steering wheel volume controls to still function. The Sony CDX-GT530UI has caught my attention - has anyone got experience of fitting one of these and does it require any extra connectors/adapters? I'd like to get away from using music CD's in the car and would prefer to use an ipod or MP3 player device instead. I'd like to remove the CD auto changer in the boot - is there something else I could put there instead? Or is it better to just scrap it and have my MP3 head unit instead?

Cheers

Martin