A 30-year-old woman with a history of peanut allergy develops sudden generalised urticaria, lip swelling, hoarse voice and wheeze shortly after eating a dessert in a restaurant. She feels dizzy on standing. Her weight is 70 kg, blood pressure 85/55 mmHg, heart rate 120/min and oxygen saturation 93% on room air. According to Australian anaphylaxis guidelines, what is the most appropriate initial dose and route of adrenaline?