Right radio code but doesn't work?!?

Had to disconnect the battery the other day and managed to source a code online through cliosport. I've done it with previous cars and it's worked. I type the code in using the thumb wheel and use the bottom button once I've finished but it still says error. After a bit it comes up with the four 0's but still doesn't work. Someone else tried to get me the code and it's the same as the one I tried entering. Any ideas?

 

It's the cd changer head unit (should have mentioned that). When the 0's show I have tried the preset buttons, just beeps so can't do it that way.

 

Was thinking. If the changer was put in at a later date would that be why it's not working?

 

Will be doing this Tomo. The code on the amp is different to the one on the hu.

http://www.renaultforums.co.uk/showthread.php?t=26560#/forumsite/20488/topics/26560?page=1

 

Sorted that works. Serial number for the code is on the amp in the boot