Co-producing principles to guide health research: an illustrative case study from an eating disorder research clinic oleh Cat Papastavrou Brooks, Eshika Kafle, Natali Butt, Dave Chawner, Anna Day, Chloë Elsby-Pearson, Emily Elson, John Hammond, Penny Herbert, Catherine L. Jenkins, Zach Johnson, Sarah Helen Keith-Roach, Eirini Papasileka, Stella Reeves, Natasha Stewart, Nicola Gilbert, Helen Startup