1 Data Research, Innovation and Virtual Environments (DRIVE), NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK. s.visram@ucl.ac.uk.
2 UCL Interaction Centre, Department of Computer Science, University College London, London, UK. s.visram@ucl.ac.uk.
3 UCL Interaction Centre, Department of Computer Science, University College London, London, UK.
4 Data Research, Innovation and Virtual Environments (DRIVE), NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.