Focus groups
All intervention sites were invited, and agreed, to participate. Individual therapists and therapy assistants were provided with information about this aspect of the study. Those agreeing to participate provided written informed consent.Face to face focus groups were facilitated by the lead researcher (LJ). Groups lasted approximately one hour, and followed a topic guide, broadly structured around the NPT framework (Focus group transcripts were analysed by two researchers (LJ and JM)–allowing for sense checking of ideas, and the exploration of multiple assumptions and interpretations, rather than for consensus of meaning. Following data familiarisation, a hybrid approach [Data then underwent theory-driven analysis, guided by the four main constructs of NPT [