Jon is an Honorary Research Fellow at the University of Edinburgh and Proteomics Facility Lead at the Royal Free London NHS Hospital. With over 25 years of experience in metabolic bone disease research, clinical chemistry, and laboratory medicine, he has developed and validated numerous biomarker assays for both research and clinical diagnostics, including LC–MS/MS methods for vitamin D metabolites (25(OH)D, 24,25- and 1,25(OH)₂D). He has also established reference intervals and multiplex ratios that reveal dynamic aspects of vitamin D metabolism. Jon’s current research focuses on osteoanabolic treatments for bone stress fractures and the application of bone turnover and calcium–phosphate homeostasis markers to support the diagnosis and monitoring of rare bone and mineral disorders.