Coding results
All acceptability constructs were coded, except ‘self efficacy’ was not coded for the trial or SGC attendance, and though ‘opportunity costs’ was coded in relation to attending sessions it was not coded specifically in relation to participating in either group. Most codes related to ‘perceived effectiveness’ (50 in 7 interviews SGC, 46 in 6 interviews ACT). Findings are presented as themes within each acceptability construct, supported by illustrative quotes (quotes are linked to a participant via participant number (1–80), gender (m/F) and the number of sessions attended out of 10).