Well done with the images.
Not Irish, but from Sheffield, Martin, Hall & Co.
The Gothic letters appear to be EPGS - Electro Plated German Silver, a term that fell out of fashion, for marketing reasons, following the advent of the Great War, so the jug can be dated to pre-1914.
Can you post a close-up of the engraving? I ask because most items marked 'Hard Soldered' were destined for commercial use.