So as others have alluded to the indication is for a very mild winter. The percentile chance of the winter being 'very mild' is the highest that the model data (that they are now using) has ever shown. Not sure how long this has been used for as I've only been involved in these briefings for 3 years.
Any colder weather is expected early in the season and not to be long lasting. Obviously this is seen as welcome news for all concerned (though not for winter weather fans!)
The likelihood is also for wetter than average conditions, especially in the North & West, with flood risks for 'normal' associated areas, though rainfall could be average for South East England. Further afield , the expectation is for an exceptionally dry winter over Iberia & France which would lead to drought conditions going forward in these areas.