Debut hour of stand-up and characters from the 'out-and-out hilarious' (Stage) Derek Mitchell (Ted Lasso), whose popular online sketches as @letsdoubledutch have generated over 250 million views and a dedicated following.   Right off the back of a 44-date European tour, the show is about the journey from being an outsider to a sort-of insider and making sense of all the cultural nonsense and confusion in between.   'The biggest laughs of the night' ( /