Doorbell Wired Installation problem UK

I am installing a doorbell wired in the UK. I am powering direct from a Ring power adapter via the old bell wiring, I am getting 24VDC at the ring unit. I never get to the spinning white light - I just get a flashing blue light pulsing every second or so. I have tried the reset button, makes no difference. If I put the power source direct onto the bell it just goes a solid blue and reset button has no impact. Totally lost, please help!