You don’t wanna miss Diwali in Bali. It is an experience to have at least once in a lifetime. This Hindu celebration, the festival of light or silence in Bali, takes place on the 7th of November and has different forms of manifestationin Hindu Bali than in India. The most impressive is that it ends in offerings and lights. I have witnessed it by mistake and have been impressed. The specific bamboo decorations are a wonder.
Best flights I found throughout October and November are with Philippine Airlines from London. The plus is the transit time, quite low and manageable.