I have found out now how to remove the radio and have confirmed that there is a DIN size aperture behind it. The connectors are specials so may have to have an inline connector to allow restoration to original.
The only difficulty still to be investigated is the common earth lines. I'm told that the commoning is done iside the centre console, so hopefully that will be easy enough to sort out.
The reason for change is that I have been unable to repair the LCD display and besides that, I changed over to Minidisc with CD changer some time ago. I don't have cassette tapes anymore!
I hope this might help someone else in the future. Contact me by email for detailed instructions on removal etc.