This is a very competitive price for a 6GB GTX 1060 - same as a 3GB in fact.
Go to the Laptops Direct site and sign up for a trial membership of Which for £1.00. You will receive an email with a £20.00 discount code within one hour. I used it to purchase this card but it should work with all purchases over £200 on their website.
You'll need to cancel your trial within one month unless you want to continue the subscription and be charged monthly.
4 day postage is £4.95 and a 1.5% surcharge on all credit cards.