Constant app problems

I’m puzzled why you see your and your neighbour’s system. Are they on the same network?

Many issues for folk here have been resolved with a router and speakers shutdown, a few minutes wait and then a phased restart. Get the router going first and wait till the wifi is up and running. Then restart speakers one at a time. It’s a good idea at this stage to set reserved ip addresses - if you don’t know how someone here can probably talk you through it. 
Try this first and see how it goes. 

My neighbours are not on the same network, unless they have hacked into it! Thanks for the suggestion, I’ll look into your process at the weekend, but I still find it very annoying in this plug and play generation, Sonos don’t/can’t! 
 

Not sure why you are seeing their system then. 
By the way, hopefully we can improve the usefulness of your system, rather than its uselessness!

My WiFi is password protected, although it may be time to change it and see what the result is. Thanks.

If you can see your neighbor’s Sonos while on your WiFi, or he can see yours, it’s absolutely time to change passwords.

The Sonos controller must be on the same subnet as the speakers are. That means, if you or anyone else can see/control multiple systems, the Sonos systems are on your WiFi.