Autumn Winter '13 has some great scarves that will become grails in the next few years. If you don't buy now, you may regret later on. I'm just saying...
Since you're from the UK, your choices are limited since you have to pay customs if buy from non-EU country. There are great European sellers on eBay: estherparis, framboise4055, tiger0308, shopfranceinc (she's based in the US but shops for clients in France every 6-8 weeks and can ship from there). They are scarf collectors and you get what you pay for, condition-wise.
If you don't mind paying customs, there are great websites:
http://www.luxury-scarves.com/en/0_home/index.php - from Zurich
http://www.its-all-goode.com/NEWEST-TREASURES_c21.htm - from New York
These are sellers whom I have never seen a single fake from.
Ann's Fab Finds have authentic scarves but they are from Michigan in the US, their photos leaves a lot to be desired in order to judge condition. You may end up with a hassle of returning cross the ocean.