If your coming out in Dec or Jan try and avoid the xmas, new year times as it gets very busy on the flights and they are hard to get plus its more expensive at that time with all the kiwis coming home for xmas and new year.
I have only flew with either Emirates or Singapore Airlines,they both fly into Manchester, and are excellent airlines.
There are lots of places for stopovers anywhere in Asia,take your pick.
Hope you make it over its a great country,lots to see and do,and at the time you are coming it will be middle of summer so should get some good weather. Btw Bolty is in Perth i believe about 5-6 hours flight away.