From the manual (you can check it out athttp://topix.landrover.jlrext.com)
The service indicator will inform when nxt service is due but in absence of indicator
A Service - 16,000 miles / 26,000 km or 12 months
B Service -16,000 miles / 26,000 km or 12 months after the previous A Service
and then again A Service etc.