pHATdac + Pi Zero software?

appreciate it doesn't help crispyxuk, but I can confirm that Volumio (v1.55) does boot on a Pi Zero, after running the following on an original Pi B :

sudo apt-get update
sudo apt-get install binutils
sudo rpi-update

then put the SD card into the Pi Zero and run the pHAT install script

you have to run it headless, ie SSH into both Pi to run those commands...

Cheers,
Tracy.