Colin2040 said "The Sonos system is designed for dummies . The Sonos will travel west and take up residence there and it runs from a storage device which I will set up once I have all the back ups and computers with the same library.
In the flat I wish to set up something using the laptop, a simple amp/dac linked to the laptop. I suppose the question is , is it as simple as that or do I need any other device in the chain or is there a better way".
The Sonos is an audio player/streamer operating with firmware. You need to let it know where your library of music is located, and it will output the music to your amp > speakers (if you have Sonos Connect). If you use a Laptop you need software to do the same job as the Sonos box. Just like the Sonos box the software will need to know where your library of music is stored (you can tell it multiple locations if your music is spead about various locations for example on the local hard drive, a NAS etc, a mapped USB stick). The software will then output the music to amp and speakers. You can use analogue outputs from the built in soundcard. This will generally give poor sound quality. You can use a USB DAC (much better for sound quality, and an asynchronous USB DAC is pretty much the standard these days) > amp > speakers. Obviously computer software players are a bit more tricky to configure correctly, but they also give greater flexibilty. For example they will playback hi-res downloads with ease 24/192 and higher. Sonos is limited to 16/44.1 or 16/48 resolution files.
I use a dedicated media centre PC. It stores the music on the local hard drive, and has an optical digital output, which I currently use to connect to a digital AV amp. I have my music backed up on a portable USB drive, and a NAS (you cannot be too careful).