Your first mark is an electroplate mark of Alexander Clark Manufacturing Co. The 7dwt mark shows that 7 pennyweights of silver was used in the process of plating the set of (probably 6) items.
The second mark is also an electroplate mark. Although I don’t know who S&L were, EP over NS stands for electroplated nickel silver. The A is a measure of plating quality where A1 is normally the best quality.
The third mark is a sterling silver hallmark. JGLtd is Joseph Gloster Ltd and the hallmark is Birmingham, 1960.
I don’t see anything familiar on the last mark so I can’t help with that.