Robert Allison was a Scottish silversmith operating around the mid 20th century. Much of his work was of a Celtic design and included designs such as stags, Celtic knots and crosses. His mark is often found on brooches but he has also been associated with Scottish weapons such as dirks.
His maker’s mark consists of RA in an oval and is often assayed in Glasgow.

Vintage Scottish silver Robert Allison 1957 central banded aventurine brooch. Stamped with makers mark. 15.38 grams total weight.
Sold for US$85 at Bayside Auctions in 2022

A Scottish Iona silver brooch with long boat detail, hallmarked Glasgow 1954, maker Robert Allison. Approx. 1″ diameter
Sold for £40 at Claydon Auctioneers Ltd in 2022