When John Center and his family immigrated to Australia in 1908, James Robertson Sr and his son, James Jr took over the premises at 64 Grove Street Edinburgh. James Jr. would have been 15 years old at that time. Early advertisements indicated that James Robertson was "successor to John Center & Son". James Robertson Sr was a Seaforth Highlander, competition piper, and Pipe Major.  During the late 1800's he was both Pipe Major and music teacher at Wellington Reformatory.  He died in July 1915.

James Jr. saw active duty from 1914 to 1918 with the 4th and 9th Battalions of the Royal Scots. He served as Pipe Major until 1925, when he returned home. During his active duty he became close friends with Alexander Ross, who was awarded a patent for "Improvements or relating to Bag Pipes" in June 1924. Robertson manufactured this bagpipe, which was very distinctive in profile and detail. These attributes carried over and can be seen in Robertson's Great Highland Bagpipe from that same period.
The earliest example of a Robertson bagpipe can be seen below. This bagpipe was purchased new in 1914 from the Robertson shop in Edinburgh. James Jr. would have been away with the war, so we can assume that the bagpipe was made by James Sr. Bernie Leigh added the silver many decades later.
It is interesting to note several aspects of the bagpipe that diminished or disappeared after James Jr. returned in 1925 and then reappeared later, in the 1940's and beyond. The very "square" and "angular" profiles of the tuning chambers and bell are obvious. The beading is relatively typical of GHB's in general. The mounts reflect the general profile and detail of what we expect to find on a Robertson bagpipe, however they are much smaller in diameter.
By all accounts James Jr. was a man of great ability. He authored music books, a booklet regarding the materials and other matters of the Great Highland Bagpipe, and he invented bagpipe seasoning that is still in production today.
As a general observation, the profile of Robertson bagpipes fell into three categories. The most radical change occurred when they abandoned the early 1920's profile. The dates are approximations as some changes were gradual.
Robertson Bagpipes 1920's into the 1930's - This version had very severe angles. The tuning chambers flared out and they cut back in at a 90 degree angle. Beads were very wide and flat. Combing was typical of other makes.

Robertson Bagpipes 1930's to 1940's - James Martin was the shop foreman and the profile changed. The sides of the tuning chamber became straight. Beads became smaller and more rounded.

Robertson Bagpipes 1950 to 1967 - George Kilgour was shop foreman. The bagpipe became iconic with small rounded beads, tight TPI combing, and the profile became convex or "bulbous". Projecting mounts were massive.