Oh no problem dognose, I'm glad you appreciate it!
I´ll post the related information as I was told about in the original language (Spanish), and the try to translate it as good as I can!
Sobre “JPG” se trata de la empresa JoyerÃa y PlaterÃa Guernica. Utilizaron este tipo de marcas para sus cubiertos de alpaca plateada, tuvieron también muchas marcas distintas. A lo largo de sus casi 100 años de historia, que aún existe, han pasado por muchas dificultades incluido el bombardeo de su ciudad. Se asociaron con algunas empresas de cubiertos como Dalia y creo que fabricaban los cubiertos de la marca Meneses, en estos momentos no se como están, con la crisis supongo que no les ira muy bien. Existe un libro que habla de ellos, se edito como aniversario de sus 75 años de historia.
"About "JPG", we are talking about the company "Joyeria y Plateria de Guernica" (Guernica's Silversmithing and Jewelry). They used this kind of mark for their nickel silver* silverware; they also had many other different marks. Trough it´s 100 years of history (as it still exists**), they have suffered many difficulties, alongside the bombing of their hometown. They associated with different flatware companies, as Dalia, and I believe them to have forked the flatware of the Meneses brand. It's uncertain their current situation**, I believe with the actual crisis they won't be doing very good. There exists and history book talking about them, edited when the company grew 75 years old."
*I am not a silver expert, so sorry if these aren´t silverware but nickel silver silverware. The ones showed do not showcase year of making, and if I ever get an expert to look into them I'll tell you all what they came out to be).
**It seems as if they do not exist anymore, as from 2008 they entered into liquidation, finally ending in 2011. A subsidiary was made by former employees, being called "Servicios De Mesa De Gernika" (Guernica's Place Setting-Sets").
Again, this information was provided by the owner of the previously mentioned site.
Happy holy week!