There are headlamp fuses and are indicated on the fuse panel and pull down chart within the panel.
However you won't be going anywhere until your brakes are sorted out. The indicator lamp when on to alert you to a critical condition regarding the brakes, specifically low pressure or low fluid level. Do you know which? Is the fluid within the square reservoir at the required level?
If it's at the required level you have lo pressure in system 1 or 2. Do you have a RR/Bentley specialist that you can bring the car to?