Thanks to John and KatG for replies and somewhat sobering news.
I am guessing that my new plants have been propagated in warm temperatures, either artificial or internationally. I am also guessing that they have been treated with flower inducing hormone. That is somewhat confirmed by finding a Dutch website which sells Calocephalus in bulk to supermarkets, along with orchids and Anthurium. Ideal plants for the pre-spring house plant market. There is stil three weeks or so before the garden centres will be selling the influx of perennials such as lavender, helichrysum and pelargonium.
My plants give no clue to the species grown. There might be taxonomic difficulties here. Calocephalus leuca is described, in its natural habitat as being rhizomatous and occuring in mainly desert areas across the southern half of Australia. There is another plant Leucophracta, once Calocephalus brownii which is described as bush or rounded shape which clings to the salty coastal southern areas of Australia. It seems as though this might be my garden centre plant.
So, I will cut away all the flowers, reducing the plant by about half, keep it inside at night until April then plant in a sunny place with maximum drainage. And wait to see what happens.