I would be sowing them now, Mandy, in a pot of gritty, loam based compost. Sprinkle the seed on the surface of the compost and cover with a thin layer of grit. Stick the pot outside in the shade. We haven't finished with the winter frost and snow yet (only March 2!) and exposure to these will help germination. The source of the seed indicates that it might not be as fresh as desirable so don't be too disapointed if it doesn't germinate for a couple of years yet. During the waiting period don't let the compost dry out.