The 6800 is 250W compared to the 3070's 220W.
The 3070's also a bit cheaper... For 1440p, if I was in the market for a $500 card, which I'm not, the 3070 still looks better IMO.
Where can you buy the 3070 for less than £550?
Apart from Founders, which we all know will be sold out in seconds......
The 3070 isn't a £500 card, it's closer to a £600 card. So just spend the little extra and get a 3080 competitor (6800xt)?
Or spend a bit less and get a 3070 competitor - the 6800.
You can't use RRP to compare against Nvidia when that's not their actual prices.