PoE Injector or PoE Switch?

Looking to get an IP CCTV setup at home and already have cat 5 points in most rooms of the house (single cable run and point unfortunately though as electrician who did the cabling at the time didn't ask and it was too late after the walls were plastered etc.).

From where I am looking to have the cameras setup, one side of the house should be able to run directly to an NVR (with PoE) with the other side of the house needing either to run to a point with an PoE switch then into a point where the existing house cable is OR each camera has its own PoE injector then runs to the nearest cable point inside.

Scan only have two PoE injectors (one in stock) and various PoE switches. Any recommendations on switches?