RR did not sell Shadows as hearses - all conversions were third party. My guess would be that most if not all Shadow hearses are one-offs, more comparable to stretch limos based on wacky choices like Hummers, MINIs, Countachs etc than genuine coachbuilder conversions. Not aware of any UK coachbuilders who did Shadow hearses - there were many cheaper base cars of the same size (Granadas, Mercs) and then the next size up tended to be Daimler Limousine DS420, which was the successor from hearses based on big 50s Rollers and Austin/Van DenPlas Princesses when they stopped. My next guess would be that any Shadow hearses were not done from new-build cars, but more likely using cheap old Shadows 10-20 years after they left the factory, and may have been in poor condition/unwanted.