Can anyone tell me if there is a website, or any other information
source, that lists the dates and preferrably the times when the
Christmas sales start?

I would like this list to be broken down by store name (e.g. Harrods,
Selfridges) and if possible, location (e.g. London, Manchester).

I would ideally like to find a website that has all the major stores
listed, the date and time of start and end of sale (Winter and
Summer), location (even non-UK if possible) and any special offers the
store might have (again, if possible).

I know I can look this up individually and I know of a site called:
http://www.shoppingsearch.co.uk/january-sales.htm
which I think is a little crude and doesn't list many stores.

I have tried "January Sales" in Google, but just get sites with
cluttered and hoc lists of sales, definitely not what I'm after.