The connect amp is £399 more than what I wanted to pay
I have my 12TB media server but just thought the S2 would be the easiest option.
Get up play a song/album on my phone and listen to it in the shower.
So what I would do is install the sonos software on the server and control it from the phone?
Sonos does not require a server software to operate, the app will pick up your Sonos network and you can control it, as long as you have at least one zone player (i.e. a Play 3, Play 5, Connect: AMP or the ZP90 whatever they call it these days), it's all ran from the zoneplayers.
You point it to your nas/media server etc, it will index it and give you a nice interface on Android, iOS, PC etc to browse and play your music. I have a readynas + Spotify Premium sub which I use which is awesome. The radio function is also very good, I sometimes play Five Live whilst showering.
It can be initially expensive, but personally I think it's the best solution for multi room music. You can get the bug easily with it as mentioned.
I guess your cheaper options would involve getting a micro hifi or something, or a cheap amp to power the speakers, and just plug your phone in via line in.
I suggest you go down to a Richersounds\PC World etc and have a play, or look at some vids on Youtube. I think it's a more convinient option as you dont need to faff around with any wires, my bathroom zoneplayer just sits in the corner in the cupboard, i've never had to touch it, and we have 4 tablets, 3 laptops, 1 PC and 2 smartphones which can control our Sonos players always at hand.