IO/910 Scottish Celtic vintage Viking ship silver retailer brooch, Girls Association 1930s to 1950s

A vintage silver Viking ship brooch which has to the rear in large letters G A, Girls Association, a Christian religious association for girls similar to the retailer Boys Brigade. It has no hallmark or makers stamp but the Viking ship is an Alexander Ritchie design, there are two forms of this brooch one plain, this one and one enamelled, the enamel brooch dates from the 1930s and the plain silver one, which is the most common of the two, is mostly post war and was produced into the 1950s, these mostly originated in Scotland .
There is very little information about these brooches which is a pity as they are generally well made, I would like to know who made them.