1. CRC Child and Family Research Group, School of Psychology, University of Exeter, Exeter EX4 4QG, UK
2. CRC Child and Family Research Group, Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TP, UK
3. Royal Orthopaedic Hospital Oncology Service, Royal Orthopaedic Hospital NHS Trust, Woodlands, Northfield, Birmingham B 31 4111, UK