Abbey theatre, DublinDenise Gough plays out Portia's bleak 30th, defined by family resentments, misogyny and the spectral presence of her dead twin, in this disturbing drama It is not only the prying eyes of rural neighbours that make Portia Coughlan (Denise Gough) feel trapped. In Marina Carr's blistering drama from 1996, the anti-heroine of the title feels bound for life to her dead twin, Gabriel, and to the Belmon…