It’s not unknown that when multi circuits fail with a 200 series disco that there’s an issue with the fusible links (blown due to corrosion) they are located behind the battery and rapped in the fabric of the wiring loom that runs along the inner wing, there will be a small bulge in the loom where the positioned.
I would think that your vehicles links would have been replaced by now, but may not have been updated possibly by the fitment of a 300 series engine bay fuse box, although there was an aftermarket fusible loom produced for the early RR which also was known to suffer the same issue I believe.
Other than that check earth connections which may be in the front footwells like the 300s.