LONDON (Reuters) - Australia and New Zealand Banking Group Ltd (ANZ), whose gold bullion business is one of Asia’s largest, said on Thursday it was closing its precious metals vault in Singapore. FILE PHOTO: An ANZ bank logo is pictured in Sydney, Australia April 23, 2018. REUTERS/Edgar Su/File Photo The move follows the bank’s sale last year of its stake in an exchange-traded fund backed by physical gold and sources say it is part of a scaling back of ANZ’s precious metals business. The bank...