A conundrum here. The Spotify client available via Welcome (which sets up a PPA) is very old - 0.9.17.
The most up-to-date version is always in http://repository.spotify.com/pool/non-free/s/spotify-client/ and is currently 0.14.124 (64-bit).
The choices are either continue to link to the PPA, link to the folder or ask Spotify to update the PPA. I’ve just done the last …
Replying to myself - but they replied to me and completely misunderstood what I was asking for 
Bit confused here - Spotify on their website still link the older “stable” PPA, even a lot of other websites on the internet. It would make sense for UM Welcome to link to that PPA too.
After manually installing the 0.14.124 deb, everything still seems to work fine (still got that bug with local files) and I’ve somehow lost integration in the sound applet. 
Even more odd it removed the original PPA. 
Well… I think I’ll stick with the stable one for now.