Yes, EP and A1 are clear indicators of electroplate. Your picture shows another electroplate mark - in this case it’s the mark of Deykin & Harrison of Birmingham; the fleur-de-lis and man in a boat are their trademarks and the lettering reads D&H.
Electroplate generally has very little value. Clearly, as there is no real silver content, there is no value there. So it’s just utility value - and there is little demand for it. In addition electroplate can be seriously devalued (from the odd pound or two down to nothing at all) if there is any plating damage or loss.