Thank God who made the British Isles... heavy sarcasm at the expense of the 'flanneled fools' of "The Islanders", although these cricketers have a robustly antiquated air about them. Kipling is clearly unimpressed by their worship of the game, and their sense of superiority to heathen foreigners.
Sussex Cavalcade (Ankers & Smith, Hawthornes Publications, Sevenoaks, 1992, rev. 1997) says (p. 61), apropos of the Almanac: '... June featured Alfred Mynn at the wicket. He was a famous Kent all-rounder of the 1830s and 1840s who weighed some 18 stone.'
a willow wand Cricket bats are made of willow wood.
hide and cork and twine Cricket balls have (or had) a core of cork, covered in leather and bound with twine.