Well , carrots and peas can still be sown if you have a cold frame or tunnel in a mild areas.
You can also plant autumn onion sets for a crop in early to mid-summer next year.
Garlic can still be planted in mild areas having free-draining soil.
Radishes, mustard cress, and winter lettuces can be sown in grow-bags under glass, in a poly tunnel or on a windowsill.
Above all, this time of year is a good time for digging over vacant areas of the vegetable plot, as the approaching cold weather will help to improve the soil structure by breaking it down into crumbly particles. After digging, cover any vacant ground with black polythene, to prevent re-colonisation by weeds.