Steve, I'm not sure either. The Genus is Fumaria but there are a number of species recorded on CNM; perhaps best to check them all in regard to similarities? The species so far recorded on Mts Majura/Ainslie is Fumaria muralis subsp. muralis.
I have taken another dozen photos of these flowers with better light. You can see these additional photos in the following Google Photos album: https://photos.app.goo.gl/53FtWsnFVDD3i87j8
Steve you can put up to five photos on the one sighting on Canberra Nature Map. To ID individual Fumitory we need a shot of teh leaves to see whether they are channeled or not. WE need to compare the length of the flower stalk to teh flowering bit the number of flowers and flower shape