This research is funded by the NIHR Health Technology Assessment (ref 15/130/07).  The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

Sponsor: University of Bristol (ref 2738)

Ethical approval: South West - Central Bristol Research Ethics Committee (ref:REC: 17/SW/0089)

MHRA: 03299/0021/001-0001

Trial registration:

• ISRCTN: ISRCTN84540529 (Date registered: 05/06/2017)
• EudraCT: 2017-000688-34