I don't think that's true anymore. The ban wasn't formally finalised and was quietly dropped during the pandemic. The store I work at still sells energy drinks to under 16s. We used to have to check, but they changed it and took the warning off our tills.
ETA: stores can implement their own policies though, if they do wish to age check people buying energy drinks.
Smashing Security or Darknet Diaries. I always put them on before bed and fall asleep. I have to relisten from the latest bit I remember to make sure I get all the information.
For the UK legislation: https://www.legislation.gov.uk/ukpga/Vict/2-3/47/section/54
Paragraph 16.