I just use all year round but plant them out closer together to get a smaller cauliflower. I've just sown some last week to be ready about early mid September and will sow more to be ready in the autumn I've got some in the polly tunnel that were sown last autumn and will be ready soon.
I find all year round to be a very successful tasty variety that does well most years here in the North east.
I won the cauliflower section in our show with one of them so they will grow large if they have the room.
They seem to hold well but I started to take the curds quite early as I always have a good few in sown at different times