I am inclined to agree with you. It was about 40 thousand years ago when they first came to Europe and about 10 thousand years ago they came to the British Isles. Surely they must have evolved lighter skins in order to get more vitimin D. Yet the reconstruction of Cheddar man shows him to be as dark as a sub Saharn African.
A couple of the people involved in the Cheddar man reconstruction have openly admitted there was a woke political element in showing he had dark skin which is not really helpful in the long term view of things.