Originally Posted by
serfty
Why only one stopover?
-LHR-xSIN-xHKG-NRT would be valid assuming no other stopovers in Asia at the beginning of the journey. (subject to maximum segment rules).
I think the rules dictates the 1 stopover (max) at the beginning & 1 on the return (also max). OP has 2 stop-overs.
-LHR-xSIN-xHKG-NRT is valid.