I have managed to get my Play:1 speakers working again. I clicked on one of the greyed out categories in the Sonos app that wasn't working and this popped up the message that there was another update before I could proceed. 

Before carrying out the update, I rebooted the speakers and my router. I then connected them both to my router with network cables and then was able to carry out the latest update. My speakers then started functioning as surrounds again.

Unfortunately, I have not resolved the lack of a working microphone and voice services on my Beam. However, I've had this problem before and it eventually resolved itself with another update after a few months. 

Meanwhile, I still have voice control of my Beam via my Amazon Echo devices until it gets sorted.

I have now also resolved the issue with my Beam microphone and voice services.

It seems that these issues occur when there are specific updates.