Ring Keypad 1st Gen - Flashing Red Battery Light

On trying to set up a brand new Ring Keypad (part of the kit that includes base station, contact sensor, motion sensor and range extender) I only get a rapidly flashing red battery light.All the other devices are working correctly, and I have already followed the "Hold down 1" and "Hold down 5 and poke the reset hole" suggestions, and have tried different cables and power supplies to rule out a fault there, all to no avail.Any suggestions on what to do next?