How exciting. I think you have found a new species. I have emailed Keith NMcDougall, who looks after this subject in this area. The fluffy stuff looks as if it might be natural. Though it could be aphids.
Keith replied to my email. He thinks it is Bossiaea riparia, which often has flowers in pairs. The Type specimen (the specimen from which the species was described) is from the Lake George area, and the nearest recorded living population is along the Queanbeyan River. So this is a revival of an old population. Keith does not know what the white fluffy stuff is, but suggests insects. If you have a NSW collecting permit, he is happy to look at a specimen. https://keys.lucidcentral.org/keys/v3/plants_se_nsw/key/plants_se_nsw/Media/Html/entities/bossiaea_riparia.htm
Ok. I don't have a permit, so sorry about that. Very interesting to hear about this discovery. I would be interested if there are any more sites where this species is found in the area. Thanks for your help.