SR does allow for the concept of named sea regions (e.g. North Sea) and this can be assigned an ID. When this was developed we envisaged the IHO gazetter of seas would be used (http://www.marineregions.org) to provide the names - and also the coordinates for the sea region.
Thank you for setting up this site and for mentioning my paper!
My first suggestion is to change the PD model in a way that StatisticalValues become "feature types" instead of just "types". In this way we can give the PD-datasets geometry, which was my greatest concern in the mentioned paper. For HH this is already the case.