I just had to look it up, repeat-blooming Catts (beyond twice a year) being not very common. Bingo... 1/4 C. forbesii. That species is a flower machine, and clearly it imparts that to its hybrids. I'm sure B. nodosa helps too, also produces flowers over an extended period.
To be exact, each lead seems to have 2 growths / flowers per year. The entire plant, however, seems to be sending out new growths at different parts of the year. I have three divisions of this plant and they all seem to have a mind of their own, growing and blooming at different times of the year...
C. forbesii does growths/roots/flowers 2 or 3 times a year, each time producing a couple of new growths that may bloom successively. So it is a fantastic bloomer (even if unspectacular flowers), also cold-tolerant. I have C. Quinquecolor (forbesii x aclandiae) that has the multiple bloomings and cold-tolerance of forbesii with color and fragrance from aclandiae - sort of the ideal primary for my outdoor growing.