Just in case anybody stumbles across this thread in search of a solution to a similar problem I have figured it out.
I was calling it using a callback so it actually wasn't working at all.
What I had mistake for a preset loading an EQ was just how I had left the default in HISE when I exported.
Once I took it out of the callback and called it on its own it worked fine - both the default/saved in the presets that I made in HISE and any changes in DAW were retained in that project when reloading it. Happy days...