After nearly 40 years, Withnail has arrived on stage. Sean Foley directs Bruce Robinson’s adaptation, which starts with a live rock-band thumping out a few 1960s hits. The musicians take cameo roles as maids and coppers. The show needs a larger cast especially for the tea-room scene – ‘We want the finest wines available to humanity’ – which calls for a big crowd of crumbling old crocks.