Become familiar with the brake pedal test. A low mileage car means it has not been exercised and for a RR could mean trouble, especially with RR363 brake fluid based systems. A complete hydraulic rebuild, hoses, spheres, fluid can be an easy 10K job.
This is not your traditional brake/hydraulic system. Become very familiar with it.
1980 SWII LRL-41587C FInj
1976 SS LWB LRE-23114 Harkness RR