The mark with 7 cannonballs is very similar to the town mark of Bergen in Norway around 1850. Look for more marks. Looks that there is something on the rim, or? If there are no additional marks it is a mission impossible to tell more.
Those don't look like marks to me, more like careless workmanship with the punch used for the background - have seen similar technique and motifs on both silver and silverplated pieces from India, suspect from the images that yours are plated...