It is a confusingly written article. The subtitle alone would be compatible with the interpretation that NPCC is just reporting on the policy of some of its member forces, rather than actually recommending them to adopt this policy; later on in the article, it implies that it is actually the NPCC's own policy not just NPCC reporting on its member forces' policies.

If the subtitle was changed to: "The National Police Chiefs Council (NPCC) has confirmed it has recommended officers be told not to install the NHS Covid-19 app on their work smartphones" it would be clearer, if that is indeed the correct takeaway from this confusing article.