This appears to be the best price going for this speedlight at the moment. The next cheapest is the same vendor selling through Amazon Marketplace. Non-Amazon Marketplace vendors are selling this for £217 or more, according to http://www.camerapricebuster.co.uk.
CAVEAT: In spite of this statement on their website:
"All products sold by Buyacamera.co.uk are supplied through the official UK distributors and as such are covered by their twelve month guarantee" -- https://www.buyacamera.co.uk/returns.html
my Speedlight arrived without a warranty card. I called Nikon UK and they state that presenting the warranty card is a condition of their International Warranty being honoured. I called buyacamera and they explained that the Speedlight has been split from a bundle (with the D3100?) and so because the single warranty card covers both items, it cannot be sent out with either. They state that they will honour the warranty and claim that they have never had a case of Nikon refusing to service one before.
Update 11 Dec 2010: Now reduced by £5