I gave my copy of Nickerson book to a friend, so I can't resource, but I recall, he did feel the original Woodward 12 was better than Purdey copy of Woodward action, but his fondness for the Woodward action might explain why he stayed with Purdey rather going to Boss. Of course it could be he felt the same as a past King of England, that " Boss were great guns, but too expensive."
This is my take away as well except the Boss pricing statement. I don’t think price was going to influence Nickerson’s decision.
More likely was the fact that he wanted to stay as close to Woodward as he could and the Purdey was the best option.
Another factor could be that Boss had VERY limited production in the 1960 to the late 90’s era. From 1960-1980 Purdey dropped quality to meet production. Boss dropped production to maintain quality.
In the early 80’s Purdey entered a second “golden era” and built some fantastic SXS guns. (Purdey O/U guns never have had the elegance or quality of Boss O/U guns). Purdey continued building great SXS guns into the early 2110’s. Once sold to Richmont their guns are the worst they have ever built. Ribs fall off, guns fail to fire, zero attempt at regulation. They don’t even know how to check regulation. I would not be surprised if they closed Audley house any day. They have lost hundreds of thousands of pounds annually for years and have a crew who try to pass sarcasm for knowledge. They are only open due to the vast resources of the parent company.