Dunhill turned over manufacturing of its blends to Murray's, and possibly McConnell, around 1981. Murray continued to manufacture the blends under license, making changes in them and introducing Navy Rolls, which was not made by Dunhill.
Murrays stopped making the blends in 2006, IIRC, and later the licensing went to Orlik and then STG.
Dunhill made the decision to discontinue making the pipe tobaccos, and BAT, which held the licensing rights to the Dunhil blends, announced that they would stop making the pipe tobaccos in 2017, offering an 18 month extension of the STG product before shutting down further production.
STG bought the rights to continue to make the blends, but not the right to use the Dunhill name, so they used the Peterson name, which they own for the tobacco side of the business, to reboot production of the Dunhill blends.
There are numerous articles on the web