Activist Crystal Amber bets on Britain's De La Rue

(Reuters) - Activist fund Crystal Amber more than doubled its stake in De La Rue Plc , days after the banknote printer warned of "significant doubt" that it can continue as a going concern and said it would scrap its dividend to tackle mounting debt.Crystal Amber on Tuesday disclosed a stake of 14.33% as at Nov. 29, from an earlier stake of 7.12%, making the fund De La Rue's biggest investor.De La Rue also reported a first-half loss last week as it tackles stiff competition, but Crystal Amber..