By Clare Jim HONG KONG (Reuters) -China Evergrande Group on Monday sought more time from its offshore bondholders to work on a “comprehensive” and “effective” debt restructuring plan, amid signs Beijing is tightening control over the cash-strapped property group. Evergrande, once China’s top selling real estate developer, has more than $300 billion in liabilities, including nearly $20 billion of international bonds all deemed to be in default after a run of missed payments late last year. Last week, a group of Evergrande’s offshore creditors said they were ready to take “all necessary actions …