Get the winter woolies ready, but as Gavin points out above, I wouldn't put those t-shirts away just yet. ECM more than just hinting at some potential warmth.
Aside from being an outlier I don’t think, even if they were to transpire, the conditions in the ECM 00z FI section would even be as mild as it is now. Perhaps mid teens in the south, single figures in the north and really not the most noteworthy feature of the NWP output. Having said that we are getting to the stage people cherrypick FI charts in isolation when looking for a favoured scenario.
That’s not a criticism in th slightest and it is all valid and on topic and at least it gets a good bit of discussion going.
I suspect many will welcome a return to milder conditions if it occurs.
What the GFS shows for the same time period is a bit cooler http://www.wetterzentrale.de/maps/GFSOPUK00_231_48.png
So a good range of options in FI and it will be a few days before we know, which if any, of the current scenarios is most likely.