Equipping community pharmacy workers as agents for health behaviour change: developing and testing a theory-based smoking cessation intervention by Steed, L, Sohanpal, R, James, W, Rivas, C, Jumbe, S, Chater, A, Todd, A, Edwards, E, Macneil, V, Macfarlane, F, Greenhalgh, T, Griffiths, C, Eldridge, S, Taylor, S, Walton, R