The price position of the B580 in the US is a bit better than it is in the UK. RTX 4060 pricing starts 16% higher than the B580 vs 4% lower in the UK. The 7600 XT is 36% more expensive (UK 20%), 4060 Ti 60% more (UK 36%), and 7700 XT is 60% more (UK 48%).
This is why all of the US reviewers are gushing over the card. One retailer still looks to have 6750 XT stock at a reasonable price. But that aside, the B580 just blew everything below the $400 mark out of the water. In fact, on the Nvidia side, it just made everything below the 4070 obsolete (the 4060 Ti is faster, but not by much and it has 4GB less VRAM. For an extra $150...).
£250 is still a decent price. But it's not quite the knockout punch it is in the USA.