Randomization and Masking
RECRUITMENT, BLIND
Consented participants were initially randomized in blocks of 15, stratified by the site in proportions 4:4:3:4 (Group: Independent: One-to-One: TAU) using a concealed sequence on an independent web-based King’s Clinical Trials Unit system following baseline assessment. We changed following slow recruitment to allow 11–15 participant blocks and later individual randomization with equal allocation, first to 4 and then 2 arms (Group, One-to-One) following an interim analysis. The outcome assessors, trial manager, and investigators were blind to the trial arm, including the senior trial statistician until primary analysis completion.