Ustinov Studio, BathDickie Beau offers a merry miscellany, featuring stories from Ian McKellen and Fiona Shaw, in a meditation on theatre that is closer to possession than parody Dickie Beau does speak on stage " he was the National Theatre's pantomime dame in lockdown. But he's better known for channelling other voices, lip-syncing latter-day Judy Garland or a throng of famous Hamlets. An astounding Ariel in the Ust…