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ENA for member 15 is wrong as there are no more pins in the structure. It should be the same as for 16 to 21.
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Yes indeed @Tom1961 - well spotted! I can’t recall whether I forgot to put the pin in on this example or meant to take it out but forgot to update the ENAs. As I mention that this is ‘the exact same structure as before’, I think I must have forgot to put the pin in the diagram! 
Thanks for flagging this.
Seán
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