The lowest prices I find are £380 for 1070, £415 for 1070Ti and £480 for 1080 (with the cheapest with a comparable cooler being £490). At those prices, the 1070Ti seems the best bet.
I've seen alleged £350 1070s, but not actually for sale.
I just had a look...and was sceptical rather quickly when they were referencing a Gigabtye 1080 on a well known site for £392 and an ASUS ROG STRIX 1080 for £436 on the same site. Neither of which existed, of course. Oh, and £382 for a Gigabyte GTX 1080 Wndforce OC...which is actually £461. I had the same issue with camelcamelcamel, so I think the problem is with the well known site in question.
One of them did exist as I clicked through to it,and then it sold out in a few hours,and that was yesterday! Apparently some other place price matched and it went out of stock. People ordered them.
You need to be quick on all the deals - loads and loads of deals in the last four weeks(including yesterday) on the GTX1080 for between £430 to £450,and it also comes with a copy of Destiny 2 from many retailers(you need to check for the eligible ones):
https://www.geforce.com/whats-new/articles/destiny-2-geforce-gtx-bundle-last-chance
If you sell the copy,even more money off. People have got those deals on this very forum,hence why the GTX1070TI has got such a tepid reception here!
The same goes with the GTX1070 - just the week before last helped a mate do a build with a GTX1070,which cost £365ish.
Remember its not even Black Friday or Cyber Monday,so there could be more deals.
Its why I told people those deals were good - sadly the GTX1070TI only has served to make the GTX1070 and GTX1080 more expensive,since the downward pricing of the GTX1080 was also pushing the GTX1070 down to the price it should have been.
Edit!!
OcUK,have the GTX1070 on pre-order for £350:
https://www.overclockers.co.uk/zota...s-graphics-card-zt-p10700g-10m-gx-10r-zt.html
Just looked around the GTX1070 can be had for £360 to £370 quite easily.