Steinel XLED 2 z-wave, can't pair with Homey

Hi, I’m a recent convert to Homey, have been using Home Assistant for a while on a pi, lost heart there after something updated and my scripts didn’t work anymore…

I have a Steinel XLED 2 Z-wave security light which I can’t get to pair with Homey.

I have the Steinel app installed, and am carefully following the instructions but other than in one case the app reports no z-wave device has been found.
The one time it found it the process failed to complete, I figured Homey wasn’t close enough, i’ve since tried with the Homey powered by a battery and held about one metre away but no joy.

I’ve tried the Remove a z-wave device process in settings, it doesn’t appear to see the light either.
I’ve reset the light to factory defaults a few times.

Any guidance would be appreciated. Thanks.

A bit more information. When I check the z-wave option in Homey developer I see an unknown node in there with an unknown route.