According to the RHS AGM list, de Monica , Masterpiece Green Longpod and The Sutton are hardy to 1C, while Aquadulce and Aquadulce Claudia are hardy to -15C. This may not change your mind in pursuing with de Monica if you have previously had success with it, but may influence others who might otherwise consider it winter-hardy.
The advantage of Autumn sowing in warmer climates is that the plants have much longer to develop and should produce a better crop, they tend to avoid blackfly and the earliness can be quite significant, cropping from mid May to mid June depending on the weather rather than the second week of July.