Metadata revised 25.3.2020-MMM.
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 cannot archive publisher's version/PDF. 25.3.2020MMM. --

Author Submission & Permission Form was sent never came back as a signed document, 19.10.2020-MMM