Likely a behind the dash job I'm afraid Bob. This because you confirm all external indicators/hazards work normally. Behind the dash it may be a blown repeater bulb or LED but worth checking for any loose wires to same first.
Assuming you have an early GDI Plus 4 the dash repeaters are located in the drivers LED panel fed via the BCU. A nine pin Tyco connector C96 feeds this panel and the missing repeater o/s illumination is fed via the green/white wire to this connector from chassis loom. It may be the panel is a sealed unit with complete replacement necessary if no break in feed found, but take care not to damage the two isolating diodes on the connector.
