Expert panel process to optimise the design of a randomised controlled trial in chronic rhinosinusitis (the MACRO programme) by Blackshaw, H, Vennik, J, Philpott, C, Thomas, M, Eyles, C, Carpenter, J, Clarke, C, Morris, S, Schilder, A, Lund, V, Little, P, Durham, S, Denaxas, S, Williamson, E, Beard, D, Cook, J, Le Conte, S, Airey, K, Boardman, J, Hopkins, C