What does it mean?!

We went for a walk in Ranelagh this evening.  Walked around the place, made our way to the Luas Station then called in to Mortons and then to Superquin at the triangle and then back home.  It was 2 miles in total.  I should say that I do really like Morton's.  I feel like Ina Garten (Barefoot Contessa) shopping in the Hamptons when I am in this shop for some reason!

                       Here is a picture of the Luas Station:

              Not long after we set off I saw this  strange sign:

                              I have no idea what it means!!

                    Who are the Pembroke Commissioners?!

Edit - Here is some info about the Pembroke Commissioners