Cast to Home devices not working

[Roanntree]

Plan

Premium

Country 

UK

Device

Samsung Note 8

Operating System

 Android 9

My Question or Issue

Spotify is only casting intermittently to various Home devices. 

They are all visible on 'available devices' but when tapped they just show as endlessly 'connecting' without actually doing so. 

Occasionally the connected 'beep' sounds on the Home, but the 'connecting' status does not change. 

It might connect briefly and play music, but then the connection will drop and I can't get it back. 

Everything restarted/reinstalled, phone, WiFi, devices, caches cleared etc. 

Nothing works. The app simply won't cast to any of the four Home devices available. 

Looking through Google it seems this is very common, but was wondering if anyone has discovered a fix? 

One reason we pay for Spotify is to be able to play music all round the house!

Thanks all!