Weren't Google and Apple going to release an official app along their API? It may be that if the NHS app gets enough bad press (which apparently it should), people naturally use Google and Apple's implementation. Even people who are happy to go along the NHS will likely also want to have the Apple/Google app running as well, as they don't know from which of the two "networks" the notification will come from.
No, Google and Apple announced they are creating APIs and tools for governments to build apps - they are not releasing an App themselves.
"8. Who will create the apps and where do I find them?
Public health authorities will update or create apps which users may install if they choose to participate. Google and Apple will make available, as normal, the public health authority apps for each region in the Play Store and App Store."
