Further to all these responses. It has started working. As suggested else where in the forum I selected the generic HiFiBerry DAC and not I2S. Having previously tried to get audio from the Pi via HDMI 1 to a TV (which allowed me to also watch the very fast boot routine),
I then saw a green LED light up on the DAC board (which had not lit before). There was still no sound but Volumio was not reporting any HW or ALSA errors. I then tried HiFiBerry DAC and not I2S, the LED on the DAC board went out and when I played a track I got audio! Hurrahhh!!!
All in all, quite random and not straight forward, I was all ready to dive in to the config.txt and start altering EEPROM requests. I’m not sure how stable it will be over time, so I will keep an eye on it. The family are impressed with the GUI (a first for technology that Dad usually brings in to the house), and like the search functions.
I like the many radio options as well as the search features, which are a vast improvement on the Cambridge audio app this set up replaces.
Thanks again, hope it stays stable.