Arj Barker, lackadaisical pawnshop owner and fount of urban wisdom Dave in 'Flight of the Conchords', is a frustrating figure. When he is on song in his new show 'Let Me Do The Talking', he is quite brilliant, flitting with soulful elan between surreal flights of fancy and political invective, between honeyed whispers and (often microphone-less) shouting; these moments of faux-anger, redolent of a Saturday Night Live-era Adam Sandler, tease, cajole and consciously mislead the audience, yet just as often sting and stem from genuine humanist indignation.But Barker's dyed-in-the-wool vagueness sometimes gets the better of him; he occasionally mumbles or forgets lines, and just before the climax of one anecdote about telephones he had spent five minutes constructing, he remembered he had omitted a key detail on which the punchline depended, and was forced to go back and rectify it. It didn't help that the show had started forty minutes late (no fault whatsoever of Barker's - the previous show had overrun), as the audience were tense and restless from the off, some leaving a mere twenty minutes in to the show to make it in time for another. Barker dealt well with the first couple of departures, but appeared unsettled by about the eighth. Not an easy situation to deal with, but the faint sloppiness that loomed over the show, though absent for great swathes of it, suggested it could do with a bit of polish anyway. Still, this is splendid in parts, particularly the sequences on 'Avatar' and not wanting to hear the same song twice on his iPod, and both Barker's looseness and the lack of timekeeping at the Assembly Rooms are easy flaws to remedy. Already promising, this show will only get better.