@joncrossley 

Hi, welcome to the community.

I saw a similar feedback on the Sonos Community here:

Connect Amp keeps dropping out audio

"Hi I have 4 Connect Amps that have been working fine for some years but just recently they are dropping the Audio for a few seconds which is very annoying"

Was your current issue quite like this?

If yes, it is suggested to try the recommended suggestions on the post:

1. Set the SonosNet channel in the App’s network settings so it is at least 5 channels away from your chosen 2.4Ghz router channel, which should in turn be on fixed channel 1, 6, or 11 and ideally set at 20Mhz channel width (if the router allows).
2. Remove the router WiFi SSID from the Sonos App network settings as the local WiFi signal is no longer used and that will stop the Amps trying to hop onto your WiFi signal.

Thank you very much and best regards.