Received: 1 March 2017
Accepted: 30 January 2018
First Online: 7 February 2018
Ethics approval and consent to participate
: The study gained favourable approval by the local NHS review board (REC 14/EM/0057) on 17/03/14 and the local research governance approval was granted on 04/04/14. Written informed consent was received from parents, healthcare professionals and volunteers and written and verbal assent was received from children.
: Not applicable.
: The authors declare that they have no competing interests.
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