Citroen Radio

[douggym]

My Citroen ZX was laid up for a long period and the battery ran flat so the radio lost its code. Previously when the radio has been disconnected, I have simply entered the code and all has been well. This time the radio is not asking for a code and has three blank dashes on the screen where the code should be inserted. I have disconnected the radio again but still there is no option to enter a code. Any ideas?