Clear & till the ground, work in some compost. They need about 2 feet between plants. Full sun & consistently moist, not muddy or standing water. Put down dome slug pellets or bait traps. Try Napa cabbage if you can find it.

If you can still get hold of cabbage seedlings in a nursery or GC you have a chance, far to late to start them from seed.

You're much too late to grow cabbage, I'm afraid. Try another veg such as chard instead. As long as the area gets lots of sun, it will see you through the autumn, winter and next spring.

You might find some kale plants too - I have bought these in August before now. If you haven't tried kale it tastes rather like strong green cabbage and is supposed to be incredibly good for you. The advantage of kale over cabbage is that you can just pick a few leaves from each plant and they will go on all winter.