1. eHealth Unit, Primary Care and Population Health Research Department, University College London, Upper Third Floor, UCL Medical School (Royal Free Campus), Rowland Hill Street, London, UK
2. Centre for Implementation Science, Health Service and Population Research Department, King’s College London, 16 De Crespigny Park, Camberwell, London, UK
3. Department of Health Sciences, University of York, Seebohm Rowntree Building, Heslington, York, UK
4. Camden and Islington Mental Health Trust, 4 St Pancras Way, Kings Cross, London, UK
5. Addictions Department, King’s College London, Addiction Sciences Building, 4 Windsor Walk, Denmark Hill, London, UK