Allison Randall becomes third Jamaican to test positive

• Olympic discus thrower 'shocked' over banned diuretic• Denies knowingly taking performance-enhancing substance The Olympic discus thrower Allison Randall has become the third athlete to confirm a positive drugs test from the Jamaican trials in June following Sunday's revelations by sprinters Asafa Powell and Sherone Simpson. Randall, who competed at last year's London Games but failed to make the final, acknowledged receipt of the Jamaica Anti-doping Commission's notification of her advers...