How to remove discovered router elements

I upgraded to Hassio v85.1 today.
My system has until now not recognised my old Netgear router - but suddenly on this upgrade it seems to.
However, HA has added several new ‘sensor devices’ relating to the router … for example ‘DGND3700v2 bytes received’ and ‘DGND3700v2 bytes sent’ and 'DGND3700v2 KBytes/sec received ’ - in total about 8 of them.
I have now turned off discovery, and 'show new devices as false in device_tracker in the config.yaml - but how do I get rid of these ‘sensors’ ?
Ive edited (deleted the items not wanted) in ‘.storage/core.device_registry’ - but they keep coming back. I cant see them described elsewhere (e.g. known_devices.yaml).