"Mad Johnny" rides Through Fire and Plate Glass" - "Mad Johnny" riding out of his tunnel of fire. The man who wanted to start the festival of Britain with a motorbike plunge into the Thames is busy adding to his 158 cuts and Burns riding his bike through tunnels of flaming straw soaked in petrol, and smashing straight through plate glass wearing nothing worth mentioning except a crash helmet. "Mad Johnny" Davies, 38, Ex. R. A. F., led his "motorcycle maniacs" rodeo team at Princess Risborough (