I'm looking for a bit of guidance before I take my car to a local garage - basically my CD30 radio unit developed what seems to be a common fault where the CD drive malfunctioned causing the radio to turn on randomly etc.

I had a basic CD30 radio fitted together with the basic three line display. When looking for a replacement radio I decided to look for a CD30 which came with the slightly improved screen to display trip computer info etc.

I bought a headunit and display from ebay which I was told were paired together so no recoding needed. Unfortunately I left it to my dad to take to a local garage to fit the radio and long story short, they installed the headunit but left in the original three line display. The guy at the garage told my dad he had reprogrammed the headunit to match my car's chassis number and sure enough it worked fine with the original three line display.

When I realised what had happened I told the garage that I actually wanted both the old headunit and display to be replaced as the one I had purchased was slightly better. When I took it back to the garage I was told that they couldn't get the headunit and display to work together and I now have the "Display Safe" message on my display.

In summary, I bought a new headunit and display which (allegedly) were paired together. My local garage has apparently divorced the new headunit and paired it up with my original display. When the garage then tried to install the new display with the new (albeit reprogrammed) headunit, I now get the Display Safe message.

Basically, can I salvage the pair that are currently installed in my car? The headunit and display apparently came from the same car and all that's changed is the headunit has been divorced and programmed to pair up with my old display. Should a local garage with Tech2/Opcom etc be able to reprogramme the new headunit to work with the new display, given that they supposedly came from the same vehicle anyway?

Much obliged for any responses.