After washing, Susannah’s coloured hair is a frizzy mess making her look, in her words, “like an old rag-tag old bag”! The answer is to use a serum – but which one? Trinny has s*** loads (does she mean shed loads?) of serums. Today she chooses to go with a great all-round product: Schwarzkopf BC Oil Miracle. “It’s so good for straw”, says Trinny, and you don’t need much. The secret is to apply it to the ends of your hair, avoiding the roots. Pretty soon Susannah is looking like she just spent the morning in the salon.