Are you sure you have the right price and haven't got mixed up with the 55" version? Seems very low given the 65" TV is selling for £1400.
I can't see the 65" version dropping this low come Black Friday, but it may come close and then you'll be able to buy from a reputable retailer with an extended warranty included. Samsung store offers the standard 1 year warranty.
As mentioned above though, if you continue to get discounts on the Black Friday price on the store then it could be cheaper.