I was just typing as you replied.
I found this thread.
Which explains the issue with omxplayer!!
Anyway in Kodi I just realised you can change the audio output and select hifiberry dac…Iron Man 3 AC/DC Shoot to Thrill is now pumping out of my speakers!!!
What a fantastic product the pHAT DAC is - well done PiMoroni!!!
Now how do I control the volume without fitting an inline volume control (mind you when its in the car (where it is destined) i’ll control the audio through the amp!!!