Ikea E1743 with zigbee2mqtt assistant

I have been using zigbee2mqtt for a while now with zigbee2mqtt assistant. With this, the devices section in the zigbee2mqtt yaml file is blank, as the naming is done in the assistant.
I have recently purchased some Ikea E1743 switches and am trying to get them working. The zigbee2mqtt.io devices page lists these as supported, but notes that the ‘click’ event is depracated and I need to edit the yaml file as:

devices:
‘0x12345678’:
friendly_name: my_device
legacy: false

When I try to add a section to the yaml file for the device, the naming in zigbee2mqtt assistant is lost and none of the items work. Can anywone guide me on how to get this to work? The zigbee2mqtt does recognise the click events:
'zigbee2mqtt:info 12/13/2020, 10:17:44 AM MQTT publish: topic ‘zigbee2mqtt/Office Switch’, payload ‘{“battery”:47,“linkquality”:0,“click”:“on”}’

thanks