Thinking so far...

My thoughts on potential technologies at this point are:

• Disk store
• Dunno yet! Ideally, I'd like something very quiet. Should I conflate the audio and other possible stores e.g. films, photos? 
• Synology, other RAID off-the-shelf kit, but if so probably one that will support running a media server
• A simple RAID box - loads cheaper, + a lightweight computer to run the media server (RPi?)
• Initially, a USB disk attached to a RPi!
• Media Server
• Looking at uPnP, largely because it's there, not sure I have really looked at the alternatives
• I quite like, and am running, Minimserver, not least because its tagging is supposed to be useful for classical, and it runs on NAS boxes if/when there is one (it's Java)
• Update: I've now installed and run Rune, which is a Volumio-alike but based on a different Linux (ArchLinux 32 bit), and which runs on RPi3 just fine. It's very good, and does everything I want with no installation stress or problems. Lovely!
• Renderer platform
• Currently working on RPi 3
• Provided we go with Open Source, then it can run on lots of platforms
• Renderer software
• Initially examined volumio, but 1.55 doesn't run on RPi3, although v 2 might Real Soon Now
• Currently working with mpd, which is the basis of volumio anyway
• Incorporated upmpdcli, which provides a uPnP interface to mpd
• Control software
• Linn Kinsky loaded on phone and Mac, not very impressed so far!
• Not looked at others yet
• Speakers
• Linkwitz LXMini
• These use a miniDSP DSP 2x4 to implement the active crossover; this is available in a box or kit
• If a kit, could be driven at 24/48k directly, but then needs a miniDigi to enable this; however, that is SPDIF/TOSLink in only, and then does sample rate conversion to 48k, using an Asynchronous Rate Converter chip
• Potentially, might be worth looking at the miniDSP 2x4 HD kit, since it could be driven directly in digital, skipping a DAC/ADC step to get data into the DSP
• Amps - now there's a question... Since I need 4, around 50w, there are a few options
• Re-use: Chord 1200C + Myst TMA5? Quad 405-2 + another from EBay?
• Buy - Thomann 4 channel power amp? £180 ish
• Buy - just missed a NAD 916 6 channel 70w/channel amp on EBay - £80! Although someone is selling NAD 906 (same thing) for £140 cash hmm. 
• Build - vast array of options!
• Chip Amp LM3886 derivatives
• Audiophonics - loads of options on there, including some interesting Class D (€40 per 2x100w amp, SMPS maybe €100, other parts whatever), but still expensive compared with Thomann!