5600x can't £300 here surely? If it's a £50 increase it's £250, which puts it at the same price point as a 3700x, they've been fluctuating around that price for the past few months.
I've seen a 3900 for £325, i'll likely go with that as my patience has worn very thin with AMD on this. The delay for this announcement and additional wait for them to actually release, plus a disappointing price mark up, nah, AMD have every right to do what they're doing but in a global pandemic these companies should be ashamed of themselves.