Originally Posted by CarefreeBA

I observed HKG-LHR over the Christmas and New Year period:

• The period leading up to Christmas and the few days after, availability seemed to be readily available across most flights in most classes. However, about a month before that, there was little or nothing showing.
• The period after New Year's Day was heavily booked with lots of people travelling. Some days there would be a flight or two, some days there would be nothing. The availability popped up over different cabins. The flights at the off-peak time of the day seems to show more availability. I didn't see anything appear for the CX251/255 (overnight) flights to London where as the daytime flight was the one which had seats, albeit sparse.

Whilst I can't give any concrete advice, I'd say just use the plugin to keep a lookout daily for stuff to appear and have a somewhat-viable plan B to enact on just in case. I'd say you might have to wait till about a week before departure or closer before there'll be something.