You are correct, I have now added the "s" (School Boy Error) but I now get this:
Formula=
xdXDocument:GetDOM("ArtefactsListData")/dfs:myFields/dfs:dataFields/dfs:SharePointListItem_RW[number(xdXDocument:GetDOM("ViewOptions")/Util/fields/Count)]/xdXDocument:GetDOM("ArtefactsListData")/dfs:myFields/dfs:dataFields/d:SharePointListItem_RW/d:ID
Error=
Node-test expected.
xdXDocument:GetDOM("ArtefactsListData")/dfs:myFields/dfs:dataFields/dfs:SharePointListItem_RW[number(xdXDocument:GetDOM("ViewOptions")/Util/fields/Count)]/-->xdXDocument:GetDOM<--("ArtefactsListData")/dfs:myFields/dfs:dataFields/d:SharePointListItem_RW/d:ID
Or removing the extra bits as previously advised:
Formula=
xdXDocument:GetDOM("ArtefactsListData")/dfs:myFields/dfs:dataFields/dfs:SharePointListItem_RW[number(xdXDocument:GetDOM("ViewOptions")/Util/fields/Count)]/xdXDocument:GetDOM("ArtefactsListData")/d:ID
Error=
Node-test expected.
xdXDocument:GetDOM("ArtefactsListData")/dfs:myFields/dfs:dataFields/dfs:SharePointListItem_RW[number(xdXDocument:GetDOM("ViewOptions")/Util/fields/Count)]/-->xdXDocument:GetDOM<--("ArtefactsListData")/d:ID
Is there any way of entering this formula by clicking various commands in the rules as opposed to manually typing it in???