c1 Refereed Journal Article.  MA 30/9/13. Green in Sherpa: author's Pre-print: author can archive pre-print (ie pre-refereeing)
Author's Post-print: author can archive post-print (ie final draft post-refereeing)
Publisher's Version/PDF: author can archive publisher's version/PDF, 1.10.13-MMM. REquesed signed permission, 2.10.13-MMM. Permission received, 13.11.13-MMM. Supporting documentation added to dark upload - HD 13/11/17