getting a bit nervous about too much speculation and confusion.
The first link you give is the Catalá home page for enamel artist Angel Segura Solé, who worked both on pottery and glass. Hot enamel decoration was first put on the map by Núria and Euda Solé (most likely mother and aunt of Angel) who took part in the 1925 Art Deco exhibition in Paris. Then, at the 1929 Barcelona exhibition work of Catalan hot enamel artists Lluís Rigalt, Joan Sales, Ricard Crespo, Pere Brugués and Josep Gual was shown.
Royo is listed in the artist section of 7 Catalan enamel artists, but no further details such as dates or locations are given. The full list is Josep Mª Gol i Creus, Àngel Segura Solé (1912), Joan Cervera Martí (1912), Miquel Fruitós (1921), Royo, Francesc Elías i Bracons (1892), and Ramón Sunyer i Clarà.
Cirera is mentioned as a brand name: Àngel Segura, Mercé Cirera and Royo worked under that brand.
The second link you give shows an enameled bowl signed by Royo in 1977.
The third link you give shows a standard oil bottle made by the Gordiola glassworks in Mallorca.