Silver or Silver-plate? James Dixon & Sons Sheffield 334 Large Flask/Decanter

The photo is of the bottom of a very large 128 oz. metal flask/decanter. I found one referred to as a trophy flask…but no definitive knowledge. Research gives me a general date idea of 1930-1950’s era. I’m guessing it to be silver-plate, but I don’t know enough about the maker marks to discern the details. (Very curious as to what the “four leaf clover with X” stands for. (Mark to the far left.) If anyone has any information I’d appreciate some additional insight on this piece.

Thanks for your time.

Definitely electroplate as there are no hallmarks. I have no idea about the additional mark.

Appreciate your response…hoping someone might be familiar with “the additional mark”. =0)