Funding Acknowledgement and Disclaimer: This project (NIHR131758) is funded by the Efficacy and Mechanism Evaluation (EME) Programme, an MRC and NIHR partnership. The views expressed in this publication are those of the author(s) and not necessarily those of the MRC, NIHR or the Department of Health and Social Care.

Bristol Trials Centre Acknowledgement: This trial was designed and delivered in collaboration with the Bristol Trials Centre, a UKCRC registered clinical trials unit, which is in receipt of National Institute for Health & Care Research CTU support funding.

Sponsor Acknowledgement: This trial is sponsored by the University of Bristol.

REDCap Acknowledgement: Trial data are collected and managed using REDCap (Research Electronic Data Capture, Harris PA, et al. J Biomed Inform. 2009 Apr;42(2):377-81) hosted at the University of Bristol.