Openreach FTTP goes from the exchange to an aggregation node to a splitter node, to a fiber DP, it doesn't use the cabinets.
As I keep trying to tell people there is a huge difference between openreach FTTC and openreach FTTP.
With FTTC you are reliant on an active cabinet to translate the fiber from the exchange to the copper to end users. From what I understand those cabinets have limited backup power, they should last a few hours in an outage but beyond that you are likely out of luck. Afaict they were originally intended for low-importance broadband data services only, but our asleep at the wheel regulators have allowed the industry to migrate their voice customers to services that rely on them.
With FTTP you have active equipment at your premesis and at the telephone exchange but everything in between is passive.