Peter Clarke's advice is...
Still time to sow some winter lettuce and spinach to go into a frame, poly-tunnel, conservatory or greenhouse. Sow in modules, a few seeds in each one and put them on a warm windowsill or under cover. They will take longer to germinate and be slow to grow but after Christmas as the light levels increase and there is more day length they will start to grow away and provide late winter salad and on into spring.
If you have some perennial rocket that you grew out doors in the summer you can lift some roots and put them undercover, keep the well watered while they re-establish and you will start to get big soft leaves in the early part of next year into spring.