I have almost the same issues. When listening the Play5 (gen1) stops playing for 3-4 seconds but the Play1 don’t. 
Are isinformation S1 cause my Play5 is not supported on S2. 

Autocorrect: isinformation = using 

How are your devices connected?  If they are using WiFi then perhaps just try another 2.4 GHz WiFi channel on the main router.  I suggest using channel 1, 6, or 11 as they are non-overlapping.
 

I would also set any additional WiFi access points (if using) to the same SSID/Password credentials and channels as the main router.
 

You can maybe also consider wiring one sonos device to the main router, which switches the Sonos system to a SonosNet connection between all products, but make sure the SonosNet channel in 'Settings/System/Network' in the Sonos App is then set at least 5 channels away from the selected router 2.4ghz WiFi channel.
 

See if that resolves all the device connection/dropout issues.

Thanks. Currently with Virgin so I have the 'smart' hub which selects best channel and either 5 and 2 GHz depending on device requirements. I'll try disabling the feature and working through your suggestions. Fingers crossed.

Yes I have one of their Superhubs too (the older v2) - just for info I set my primary 2.4ghz Wifi band to channel 1 and the primary 5ghz band to 36 & 44 and run SonosNet on channel 11. All guest WiFi networks are switched off. I’ve also switched off the VM public network broadcast within my VM account online - those settings all work well in our home, but see how things go for you.

I also have many of my Sonos device IP addresses stored in the routers DHCP Reservation table as I find that assists when rebooting the entire network, following updates etc.

Hope that helps too, but you may want to try different WiFi/SonosNet channels just to see what works best in your home, just keep the 2.4ghz channels well apart using 1, 6 or channel 11.

I got help from Sonos support and i had to change the master of my groupie from Play5 to Play1. The memory in Play5 was too small.