Undertaking multi-centre randomised controlled trials in primary care: learnings and recommendations from the PULsE-AI trial researchers by Pollock, KG, Dickerson, C, Kainth, M, Lawton, S, Hurst, M, Sugrue, DM, Arden, C, Davies, DW, Martin, A-C, Sandler, B, Gordon, J, Farooqui, U, Clifton, D, Mallen, C, Rogers, J, Hill, NR, Camm, AJ, Cohen, AT