Gents,
The fact that the handle pops out when unlocked says to me that the solonoid is functioning correctly, hence why replacement parts solve nothing.
JLR dealers are not conversant with faultfinding and throw new bits at the car in an attempt to fix the issue unfortunately.
The issue appears to be a little more to do with the linkages thereafter the lock ( I will look through the workshop manual presently to establish what's what).
Whilst Gummi Pfledge and silicon spray will help the issue with the door seals sticking to the cold door frame, it won't and shouldn't be used on the widow waste seals.
The issue if window stick is caused by the top of the glass sticking to the door seal in conjunction with stiff waste seals.
If you wash your car at the same time as the cold weather, you are on a hiding to nothing. Remember that when cars are tested at low temperatures, the relative humidity is nigh on zero.
Water just seizes everything up.
I'm inclined to suggest silicon spray oil on the door linkages, hinges, handles etc, but until I review the drawings I'll hold off.