The answer is: King Richard III.
In the "International Exhibition of Sherlock Holmes: Cracking an Ancient Case," the riddle makes reference to the English king from the House of York. The reason is the word "Board" corresponds with his personal badge, which was a white boar. Besides, his enemy was the Tudor King Henry VII, wo succeeded him and whose badge was a red rose. Richard had taken Edward's throne after the latter was considered illegitimate. His story was told by William Shakespeare, who was born in Stratford-Upon-Avon. Finally, his body was found under a car park in Leicester, which explains the Jaguars and Vauxhalls car brands.