Dolph, in a nutshell it is easy for police forces to cut police staff posts to save money and backfill those posts, or at least some of them, with warranted officers.
My force has done that but not without reform of frontline, namely following a Met model where officers arrest, quick pre-cis, handover to a PHT and back out.
Cheshire do they same, arrest and then a quick handover to PRT.
What they are also doing now is using lots of retired officers to visit witnesses and take two statements, it is a really good system and an excellent use of years of experience.
My wife recently witnessed an assault, both of her statements were taken by a retired police officer in a civilian role.