i have the same problem i need to remove my citroen radio. this is what i have found:
If there are two small circular holes at each end of the faceplate, you need to push stereo removal tools (readily available from Halfords etc.) into these holes (one on each end). This will unlock the unit from the dash, and it will pull out quite easily. Then the cables can be unplugged from the rear.
hope this helps 8-)
nicky
December 2008