Wiring Ring Stick Up Camera To Existing Electrical Wires

Hi, i currently have a ring stick up camera on the outside of the my property. Its currently battery powered but i would like to change it over to wired. There is already a 3 core electrical wire local to it for an old camera system which runs through trunking along the side of the house and into a uk wall plug. Due to the distance i wouldnt be able to use the power cable ring sells. Would it be possible to attached an end to the 3 core cable and use that to power it? If so, what size barrel does the stick up camera 3rd gen use for power? Thanks.