Kane Williamson was missing from the New Zealand squad named on Monday for the Twenty20 series against England later this month because of a "minor medical issue", coach Rob Walter said. The 35-year-old former captain turned down a central contract with New Zealand Cricket for this season and also missed the home T20 series against Australia earlier this month, which the Black Caps lost 2-0. "Kane had to overcome a minor medical issue in the past month, and we both agreed he needs some more