Looks like the Xantia always has central locking, but not sure about remote control. As for the boot, the central locking can lock it, but opening the boot with the key won’t ‘centrally unlock’ the doors. Copying here from the owner’s manual: The tailgate may be isolated from the main locking system and operated independently.
Interior CENTRE CONSOLE 1. Switch panel: electric windows. 2. Switch panel: hazard warning lamps, central locking, child lock. 3. Cigarette lighter. 4. Heating-ventilation controls. 5. Storage compartment. 6. Grip Control. 7. Audio equipment. 8. Screen. 9. Electronic gearbox selector. 10. Emergency call. Page 12: Sitting ComfortablyThe clock screen or do you mean the central display has 3 bulbs in it and if its faded some or all probably have gone. There is a how to on the site showing you how to replace these. Best pull the radio out and check the plugins on the back. The van may have had a different radio in and the factory one stuck back in at sale time.
KzSz.