Cheddar Man: a Portrait of Britian's First Known Man

In 1903, in Gough’s Cave near the village of Cheddar in Somerset, in southwest England the bones of a 10,000 year old skeleton from the Mesolithic period were found. This skeleton was named Cheddar Man after it's closeness in proximity to the village of Cheddar. Scientists at the Natural History Museum and University College London were able to obtain the DNA of Cheddar Man by drilling a small hole into his skull and collecting the bone powder. By sequencing the DNA from the bone powder the scientists were able to reconstruct  Cheddar Man's face. They discovered that Cheddar Man was dark skinned, dark haired, and had blue eyes.

Cheddar Man's DNA shows that he belonged to a group of Western hunter-gatherers, who first migrated to Europe about 14,000 years ago. 10 percent of British ancestry can be traced back to this particular group. It is currently believed that light skin and dark skin variants arose in Africa 300,000  years ago. Humans first arrived in Europe around 45,000 years ago but the light skinned variant was not brought to Europe until 6,000 years ago. The light skin variant was mostly brought over from people who descended from the near east. The sequencing of Cheddar Man's DNA raises the question of why it took close to 40,000 years for Europeans to make the transition over from darker skin to light? As a person whose heritage is primarily from the British Isles, it makes me wonder why my ancestors skin color changed and could I possibly be related to Cheddar Man?  
https://www.nytimes.com/2018/02/07/world/europe/uk-cheddar-man-skeleton-skin.html
https://genographic.nationalgeographic.com/human-journey/