As above, the AWD is available full time in Sport mode and up to (I think 20mph) otherwise. However, tyres make a much bigger difference in this sort of weather. A set of Cross Climate tyres will transform the performance.
I have the factory fitted Bridgestones on my 85x which are perfectly good in the dry but not great in the wet. Had them on my previous Ateca and they were useless all year.
Unfortunately Motability will not allow a change to cross climate or winter tyres unless it’s at your own (quite considerable) expense.
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!