Speaker Companion not listing available music options

I have 4 Sonos speakers and am trying to configure Speaker Companion to play a custom message notification followed by a specific track from my Sonos music library on one of the speakers when my phone presence is detected.

I can get the custom message to play OK but when I try to select the specific track I want to play under the ‘Play this music or radio station after notification’ option the only things listed are a couple of radio stations. If I change the app to run on any one of my other speakers there is nothing at all listed for that option.

I read a similar posting on this topic and the suggested solution for making a specific track visible in the list was to first play the track through the relevant speaker and it would then it would become visible in the list in the Speaker Companion app. I have tried that several times but still the track I want to play does not appear in the list.

I raised a ticket with SmartThings support but after several days of waiting I still have heard nothing. Hoping somebody in the forum can give me some ideas to try to get the track I want to play into the selection list for the option.