Non-contact infrared thermometers compared with current approaches in primary care for children aged 5 years and under: a method comparison study by Van den Bruel, A, Verbakel, J, Wang, K, Fleming, S, Holtman, G, Glogowska, M, Morris, E, Edwards, G, Abakar Ismail, F, Curtis, K, Goetz, J, Barnes, G, Slivkova, R, Nesbitt, C, Aslam, S, Swift, E, Williams, H, Hayward, G