First Telly Addict of the New Year and second avuncular outing for my jumper, which I'm starting to like: on this week's review for the Guardian, it's three big hitters from the three big channels – Sherlock, BBC1; Endeavour, ITV1; and Treasure Island, Sky1 – thematically linked in all sorts of ways. I hope you enjoy it. My jumper, that is. Warning: contains pre-watershed nudity that may arouse some Daily Mail readers. It's here.