One autumnal novelty that has worked a treat this year is Endive Pancalieri. It tolerates cold and thrives just as all the usual lettuces are grinding to a halt.
It looks like a loose leaf lettuce but has serrated leaves rather than the rounded oakleaf we are used to, and is sold by the supermarkets in bags as 'Frisee'. Although the leaves are green they are best blanched in order to minimise the bitterness that can develop as the temperature drops. Here is the result of my experimentation:
As these are across town at the allotment I am not sure they have survived the current frost, but so fare they have been a roaring success and I will be growing them in future years so as to extend the salad season into the colder months.
p.s. Endive is a member of the chicory family. I am also growing some chicory proper to be dug up and then forced for 'chicons' still later in the growing year. Watch this space!