Seneca learning has a full revision guide for GCSE Food Preparation and Nutrition, several sections are also relevant for Hospitality and Catering - Seneca - Learn 2x Faster
Lots of great resources for revision here, including printable knowledge organisers on key topics - 14 - 16 Years - Food A Fact Of Life
Great videos and revision resources on BBC BITESIZE - GCSE Design and Technology: Food Preparation and Nutrition - BBC Teach