Best answer by Ken_Griffiths
It sounds like local wireless interference, you may want to read these two (hopefully useful) links:
Reducing Wireless Interference
Local Network Stability
If you cannot get things working correctly by following the advice in those links, you can then choose to contact Sonos Customer Care directly, using this link below:
Contact Sonos Customer Care/Twitter (24/7) etc.
Anyhow I truly hope that helps and that you get your 'likely' local wireless network issues resolved soon.?