Cortana - no "play next track", "skip track" or "play next" command for Spotify?

[RHLondon]

Plan: Premium

Country: UK

Device: PC

Operating System: Windows 10

My Question or Issue:

Cortana does not recognise "play next track", "play next" or "skip track"  commands for Spotify on my PC (Spotify integration with Cortana is otherwise working fine).

If I'm missing a setting it doesn't seem obvious, but please let me know if there is a way to instruct Cortana to play the next track on Spotify.
If not, then come on Microsoft/Spotify, this is an absolute basic necessity! Put your act in order please, it cannot be difficult - even my 2010 car radio can skip tracks by voice...
I am thinking of purchasing yet another Alexa for my PC just to get round this, which seems crazy.