I have just received my AX 241 voucher and have 80,000 BAEC miles waiting to be redeemed. Does anybody know of an origin point from which BA sell reasonable/bargain tickets either in H/B class or WT+ to HKG or SIN?

My plan is for SWMBO and I to travel to origin point with voucher/miles and then commence our journey to HKG. A fare that allows a stopover in London is preferable. Do any markets still sell Special Fares that are not on ba.com? I cannot seem to find good WT+ fares ex TIP/CAI and am unaware what booking classes economy fares are booked in. Any advice would be gratefully received!