London to Sydney flight options for 2012-09-14 returning 2012-10-02

We are trying to use up our frequent flier points which will expire soon. Calculated on 2012-08-05.

The highlighted row looks the best. Flights ex Singapore seem cheapest, while flights ex Sydney are most expensive.

Description Totals Flight LHR to SIN 2012-09-14 Flight SIN to SYD 2012-09-17 Flight SYD to SIN 2012-10-01 Flight SIN to LHR 2012-10-02
SQ points BA points GBP SQ points BA points GBP SQ points BA points GBP SQ points BA points GBP SQ points BA points GBP
SQ multicity 0 0 ?2328 ?2328 0 0 0
SQ points 204000 ?1259 59500 ?480 42500 ?217 42500 ?302 59500 ?260
Return LHR to SIN, BA points SIN to SYD to SIN 80000 ?2111 ?1731 40000 ?168 40000 ?212 ?0
SQ points, return SIN to SYD, SQ points 119000 ?1560 59500 ?480 ?820 0 59500 ?260
Return LHR to SIN, SQ points SIN to SYD to SIN 85000 ?2250 ?1731 42500 ?217 42500 ?302 ?0
multicity, multicity, SQ, SQ 102000 ?2025 ?1463 - 42500 ?302 59500 ?260
multicity, multicity, multicity, SQ 59500 ?12260 ?12000 - - 59500 ?260
SQ, SQ, one-way, one-way 102000 ?2891 59500 ?480 42500 ?217 ?2194 -