Thank you, yes that was helpful in that it prompted me to look at other starting points that are easy to reach from HK. Including all taxes the fare ex-HKG came to US$10,800 (similar from Taipei), from London $8,700 and from Tokyo $9,300. Given this choice and my destinations, I'm going to get to Tokyo on Asia Miles, start from there and save myself $1,600 on the ticket cost :-)