It's been the mildest winter I can remember in Glasgow, and we have variable winters so that will always mess with when plants come ready. My autumn salads like mizuna,mibuna pak choi etc and mustard are still fine outside, they are flowering now though. They usually die with -5c frosts but we never went lower than about -3c.
Next winter we might hit -17c again, so I think we just have to accept a bit of variability