I always thought it was covered up not merely because he was trying to contact the duke of Hamilton, but because the "peace" plan involved putting the Duke of Windsor on the throne...which is why he got "exiled" from his villa in Spain or portugal to Bermuda...
Indeed, his pro nazi sentiment is well known...thank God for the dutchess, if it wasn't for her,he wouldn't have resigned, and the Brits might have made peace...
Wasn't Hess into 'magic', the occult or some such?