VS Grinding sound from passenger front wheel

[RX25SE]

pads still look ok however I noticed there is no backing plate on the pads the piston pushes directly on the rear of the pad, I thought there was a backing plate that sat between the pad and piston.

The backing plate refers to the metal part of the pad, the bit the friction material is bonded to.

Have you actually removed the pad to see if there is any metal to metal contact?