The international wine glut has claimed more New Zealand casualties with a large corporate vineyard owner forced to seek a capital restructuring and a steady stream of smaller vineyards facing receivership or mortgagee sales. The ASX-listed Challenger Wine Trust's problems have thrown further light on the decline in vineyard values in this country.Challenger, which owns vineyards on both sides of the Tasman, had its units suspended from trading on the ASX last week, when it announced it was in confidential discussions with third parties.