Speaking for myself, I would have had more reason to be doubtful of the MetO's prediction of notable cold in Feb had their forecast from during/before the festive season of generally colder weather from the middle of January failed to materialise. I think that should be borne in mind by all of us before we begin to question their thoughts for further ahead.
As far as I can recall, they never at any time predicted there would be a major freeze in the early to middle part of the winter, although they did at one point before Christmas suggest there was an small chance of a change to colder weather happening before the turn of the year. While we are not in the middle of a big freeze, there is no doubt that the weather has generally been somewhat colder since the middle of January than it was for much of the time in December and the first half of this month. Furthermore, this coming week looks like being far from mild.