EDIT

registration id is shown correctly:
in search result from the PhycoBank portal query (Screen shot 1)
when the link of the query result is clicked (Screen shot 2a, 2b)
if a hotlink to the PhycoBank Id in a scientific paper is clicked (see above)
if a hotlink in the Vaadin User Interface is clicked (see above)

registration id is not shown if a link on a result page in the PhycoBank portal is clicked, feature request: show registration Id in all cases

when the basionym of Tetralunata pelagica is clicked (Screen shot 3b)
when the younger name is clicked from Denticula pelagica (Screen shot 3a)

This is also relevant for types

AM: in short, the registration number for names (not type designations) is missing on name pages. It exists for type designations and on registration and search result pages.