Cannot add a Ring doorbell to an existing location/system

Fitted a new Ring doorbell at my mother's house yesterday. She already has 3 stick up cameras and a few chimes installed some time ago. When I go through the "setup device" procedure the App asks me for a new location which is identical to the exixting yet shows as separate. I cannot therefore connect the new door bell to the chimes. Shouldn't the App recognise that this is the same location and group all the devices in one system? What have I done wrong??