Interview data indicated that the recruitment and randomisation procedure, and assessment methods were acceptable. Only one in four of the participants in the ACT arm of the trial completed all chapters of the book with health problems the main barrier to completion. Conclusion: Our findings indicate that a definitive trial examining the effectiveness of a telephone-supported ACT self-help intervention would not be feasible. Many aspects of the trial were acceptable to participants, including the main recruitment strategy, randomisation procedure and data collection methods. However, low recruitment numbers and poor adherence to the self-help manual indicate that a full-scale trial would not be viable. Factors that might account for low recruitment numbers are discussed and personal reflections on the research process are provided.