I agree with Andrew, I would happily place an order for that much money with Amazon (not a marketplace seller). It is most certainly worth spending extra to get that extra piece of mind rather than trying just to get the best deal.
I've never heard of bestbricedbrands (does not mean they are no good) but I can't find a phone number or an address on their website, for that reason I personally would avoid like the plague, but I'm not going to tell you what to do. I've heard of lucmos and their website only has a voicemail number (as well as webchat), the website is a bit shoddy which always puts me off.
On the whole I would stick with the big boys that have a reputation to lose and a good rep for customer service ie. amazon, play, empiredirect etc. Some people around here would avoid the likes of dixons but I've always had good service and their prices are sometimes good with discounts. I would avoid pixmania.co.uk as I hear their CS is poor and they don't always supply a UK model for certain products like TVs (not sure if this applies to camcorders).
This place supply a 'free' 2-year warranty with the HF10:
http://www.equipmentexpress.co.uk/ I've not used them but I've contacted them via phone & email in the past and they seemed ok (they are essentially a camera shop).
Always read the returns policy. Make sure the website does not deal in grey imports unless you are happy with that.