Replacing existing doorbell with Wired Ring Doorbell

I'm trying to replace my existing doorbell with a wired ring doorbell. I thought it was a simple case of taking off old, using the wires on new one, bingo! But I just realised my existing door bell does not have a separate chime but actually the burglar alarm control panel (keypad) is what chimes when the bell is pressed.

Turning off mains power from consumer unit does not turn this power off. The bell still works. I'm pretty sure the power isn't strong enough to give me a shock but I'd rather turn off the power completely before beginning installation of new doorbell.

Anyone ever seen a doorbell wired to the house alarm system? How do I safely install a new wired ring doorbell? I don't need a chime with new door bell and Ring also say in instructions that you don't use an existing chime.

Any help is appreciated.