In usually sow Winter hardy lettuces, as well as rocket, pak choi, mizuna, lamb’s lettuce and spinach, at the end of September, beginning of October for winter salads and stir-fries. All worth a try now though, Id have thought - as we rarely seem to get the freezing cold before year end, like we used to.
From February I fill any gaps with early lettuce, more spinach, early peas and mangetout in the g/h border - but the peas do tend to get in the way if you only have a small greenhouse
Remember from March there will lots of trays and pots full of germinating veg and space will be tight.