If anyone knows any other ways please post here.
1.5 - 2 cups dry milk powder
3 cups water
1 large, heaped tablespoon yoghurt from previous batch (or bought cultured yoghurt)
Vanilla, honey, syrup, preserves, chopped canned fruit, etc., for flavoring if desired.
Mix all together in a large pot
Heat mixture only until too hot to hold your small finger in it
Pour into large jar and close lid
Place jar in wide-mouth flask or wrap in tinfoil & blanket (keep warm)
Leave for about 9/10 hours
Remove the yoghurt and refrigerate