I have always loved Campanula, which are often referred to as bellflowers. They are from the Campanulaceae family and are one of the classic plants of English cottage gardens; sadly, many of the truly spectacular species don't thrive well in Sydney gardens.
However, this vigorous and reliable groundcover version (ht 15 cm) is a stalwart in my garden. It comes from the Balkans region and is sometimes known as the Serbian bellflower. It forms an excellent groundcover in sun or part-shade, and in mid-spring and early summer is covered with a profusion of pretty starry blooms coloured lavender blue or white (in the case of the cultivar 'E H Frost'). The cultivar 'E K Toogood' has a white eye to its lavender-blue flowers, and does quite well in Sydney. There is a pale pink version, 'Lisduggan', but I have never had much luck with it.
This plant likes reasonable, well-drained soil and it quite resilient. Once established, it is pretty tolerant of dry soil. It spreads by underground runners. To propagate, simply detach some of the rooted pieces at the edge of the clump in autumn or winter and replant or pot up. It fits into any garden setting where a carpet is required; it can spill over or even grow in the cracks of retaining walls in a most charming manner!