There appeares to be a shortage of Wiis at the RRP at the moment.
I used the real time stock check feature on this site,http://www.wii-consoles.co.uk/
It didn't take long before it reported stock at Dixons, I went to the site and ordered one for £179.99 + £4.95 P&P (They have run out now).
I'll let you know if it arrives!
Might be worth a try if you want to ensure you have one for xmas.
Also Expansys reckon they are getting them in on the 24th of October.http://www.expansys.com/
Hope this helps,