Thanks for this info... Omission is not intended at all!

So - it looks like there are only a few possible seats for HK-Cebu (based on arrival time in HK)
CX 925 24/12 at 16:05 from HK - J1
CX 925 24/12 at 16:05 from HK - J4 C4 D3

D being the discounted business class seat...

Book the London Heathrow - HK on redemption and ticket the D then ...