Indeed, grunger@267, Jonathan Mestel is the only British person to be a grandmaster at chess and bridge. We didn't have a chess grandmaster at all until the late Tony Miles in 1976, though Keith Richardson was awarded the Correspondence Chess version before then. That form of the game has
lost credibility now that computer chess programs are so strong.
Of course the title is awarded very differently in each game. Bridge still requires a vast accumulation of master points whereas the chess title is achieved by tournament performances and a minimum rating level. Hence chess grandmasters in their teens are not uncommon.