Qualitative evaluation of the Rehabilitation Exercise and psycholoGical support After COVID-19 InfectioN (REGAIN) randomised controlled trial (RCT): ‘you are not alone’ by Gordon McGregor, Susanne Finnegan, Martin Underwood, Joyce Yeung, James Mason, Peter Heine, Nigel Edwards, Julie Bruce, Kate Seers, Harbinder Kaur Sandhu, Helen Atherton, Sharisse Alleyne, Katie Booth, Ranjit Lall, Vivien P Nichols, Stuart Ennis, Scott McGuire, Rachel Potter, Jessica Smith, Chen Ji, Shilpa Patel, Henry Nwankwo, Kate Evans, Susie Hennings, Alastair Canaway, Grace Lobley, David Mcwilliams, Christina Jones, Emma Padfield, David Montgomery, Beatriz Lara, Becky Haley, Francesca Denton, Bartholomew Sheehan, Mariam Ratna, Elaine Fairbrother, Zoe Noakes, Bogdan Zutic, Lee Austin, Tom Forsyth, Anne Bush, Alan Bush, Patrick Sawdon, Jonathon Prosser, Lee Tompkins, Jonathon Guck, Danielle Hale, Juwairia Said, Georgie Ray, Rowena Williams, Gail Evans, Thillini Hettiarachchi, Abeesh Panicker