Yup, "they walked" was my answer too. Thought that was pretty common knowledge that the North Sea as it is now was formed as the ice from the last ice age melte

Yup, "they walked" was my answer too. Thought that was pretty common knowledge that the North Sea as it is now was formed as the ice from the last ice age melted, cutting off the British Isles into what they are now. Trawlers still occasionally pull up tree stumps etc in their nets from the Doggerland area