Sorry, but your traveling plans are confusing.
It seems that you are flying from somewhere, like London if based on your profile.

It seems that your question is what will CX do on two separate tickets; Japan-HKG (avios award) then a few hours later HKG-London on the "world of winners" ticket.
On the first leg (avios) you are allowed 1 bag. But as OW saphire (BAEC silver) you should get an extra bag. On the 2nd leg two bags.
You wish to check-through your first bag from Japan to London and then add one when in HKG.
Am I right?