Primary Shopping Areas Primary and secondary frontages - Public forum - Planning Advisory Service (PAS)

Any views on whether the NPPF para 23 + Glossary requires councils to have policies for primary and secondary frontages or just define them? Or does the NPPF suggest that policy should be for the Primary Shopping Area only. From an economic development viewpoint, percentage shopping frontage policies can be restricitve in allowing changes of use/function fo town centres. Has anyone stopped using percentage primary and secondary policeis for a town centre wide policy? Would be interested to hear from Councils on both approaches...