It’s been a while, but I’ve finally made the transition from Raspfi to Volumio.
The reason for the delay was my raspyfi stopped working and I just didn’t get the time to fix it. I’d tried re-flashing with raspyfi and volumio images with no success.
But today I spent some time and now it’s all working OK 
It seems my SD card was faulty so reflashing made no difference - not sure how I could write to it but not read. The boot was failing each time, even with the new images, which I didn’t find out until I connected it up to a monitor.
I now have a new SD card with fresh volumio image, and after a bit of fiddling with the NAS it’s up and running.
A quick reminder of my set up…
QNAP TS-210 NAS
Devolo AV200 powerline and Netgear networking from NAS to Pi
Raspberry Pi “B” Revision 1 in Shortcrust case with 5.25V 2A PSU
M2Tech HiFace 2 UDB to S/PDIF
Chord ProDAC digital interconnect
Rega DAC
Rotel Michi RHA-10 passive preamp
Rotel Michi RHB-10 power amp
Chord Solid silver interconnects
Kef Reference 105/3 speakers
QED Qudos speaker cable
I’m still suffering from stuttering and crackles at high bit rates, but I’m going to blame the network for that (even though I can stream multiple HD videos about the house simultaneously no problem) and stop trying to fix it