Siri not working with Spotify very well! Especially playlists

Hi, pretty sure I've done everything to try and fix this; but basically whenever I am out for a run I like to occasionally switch from listening to podcasts to say listening to a playlist on Spotify without having to stop and take my phone out of armband etc If I say "Hey Siri play my running playlist on Spotify" then nine times out ten it'll just play random songs on Spotify. It never seems to pick up what you say and open Spotify correctly to play that playlist. Yes, it's OK at picking up band names most of the time; but it's the playlists I've created for say running I want to access.

Any ideas? Be REALLY REALLLLY appreciated. So, annoying – sends me into a mini rage when on a nice run.