A group of three rings, comprising: a diamond three-stone ring, mounted in gold, size O, stamped

A group of three rings, comprising: a diamond three-stone ring, mounted in gold, size O, stamped 18CT PLAT; a three-stone ring set with a circular-cut sapphire between brilliant-cut diamonds, mounted in gold, size O1/2, stamped 18CT; and a sapphire and diamond cluster ring, set with an oval sapphire within a border of brilliant-cut diamonds, mounted in 18ct gold, size L, British hallmark