Airplay button/icon missing from Apple Music 2017 iMac

I used Apple Music this morning to listen to some music. I hadn't turned on my bluetooth speaker, and the pop up asked me if I wanted to use the built in speakers, I selected no.

When I then looked the airplay icon/button had gone from the top bar in Apple Music next to the volume control.

I could normally use this to play the music from Apple Music on my Mac to those speakers just by playing the track, and still have all other sounds (YouTube and system sounds etc) via the built in speakers.

Now I have to select the Bluetooth icon on the main task bar of the Mac next to the date to have sounds played through those speakers. Then switch back when done.

I'm using a 2017 iMac using the latest os and all updates installed.

It was working fine yesterday and I guess technically this morning also.

Any idea how I get the airplay icon/button, and this functionality back?

I've tried various solutions from the boards etc but nothing seems to work.Some show settings in airdrop and Handoff for airplay etc but mine doesn't

Hope you can help