No, your itinerary is not valid
You have two departures/arrivals in Asia, and so your itinerary must comply with this rule
4(e) Only one intercontinental departure and one intercontinental arrival permitted in each continent except as follows:
1. ...
2. Two permitted in Asia when one is a transfer without stopover or on direct single plane service between the Southwest Pacific and Europe.
3. ...
Your itinerary has:
- A departure from Asia at the beginning (TYO-LHR)
- An arrival in Asia at the end (SYD-TYO)
- another Arrival/Departure in the middle (ORD-xHKG-xSIN-SYD)
This last one is not the required "transfer without stopover" because it has an intra-continental flight segment (HKG-SIN)
Contrast this with your other itinerary - ORD-xHKG-SYD which is valid because it has the required transfer without stopover in HKG