What a timely topic for me....
I just returned from Singapore tonight and decided to upgrade with miles...(save those systemwides for the W fares

)...Having just checked my statement, they charged my account 25,000 miles Asia-US plus and additional 10,000 miles US Domestic upgrade

.
I'm thinking your agent in London must work part time in Singapore too...Wow, what a commute!!!
Non the less there will be a friendly phone call tomorrow!