Very much appreciated. I’ll send it shortly, just need to logon to get the code.
I can live with the format change idiosyncrasy, I just need to ‘nudge’ it onto the next track. I have very few albums with varying track formats. 
May be handy for me to create an upsample profile for Tidal/Qobuz playlists where format changes are more frequent.
I previously used a Sonore Bridge with my Naim Streamer which didn’t have this issue but the sound quality wasn’t as good as RooUPnP on a Pi 4. I wasn’t expecting this so it isn’t expectation bias, indeed I initially used these settings with better SQ, close but on back-to-back comparisons noticeably better.
Roon FLAC - off
RooUPnP - transparent
I then spotted in the thread tha you recommended to use the below settings and these resulted in a further improvement. 
Roon FLAC - on
RooUPnP - PCM 24
Thanks.