On Facebook I've just been bombarded with an ad for a 100-day Xmas calendar (see link, but I've omitted the supplier, don't want to be accused of Spamming LOL). Not for me I must say, I don't even invest in an Advent Calendar.
About a week ago I noticed that the Tesco in Stowmarket already has big displays, right at the front of the store, of the big tubs of sweets (Celebrations, Quality Street, etc) that they buy in for Christmas. I'll bet that it won't be long before Christmas cards are on their shelves too ;-)