CJ for Cox Jewellery is with the Birmingham stamp, not the Edinburgh one in which, according to the thing I put above, stands for Caithness Glass.
But your article says the the Edinburgh pieces were made by Scotia silver.
(I gave up on working out hallmarks a long time ago.)
In the article, it says too, that the later bits used less silver metal (for the cost), but I don't think this particular ring is one of those - the metal is quite solid there and definitely looks individually worked by an artist who knows what they are doing.