Ainsley Harriott celebrates grains and pulses, making seared tuna, mixed tomato and bean salad with an anchovy and tomato dressing for a taste of the Mediterranean. The chef has a masterclass in milling at the Shipton Flour Mill before making dough for a margherita pizza, while Joseph Denison Carey meets Kat from the Crumpetorium to find out what makes her artisan crumpets so irresistible