This is now a really simple task, I spent a LOT of time making changes to my config to support the device over MQTT after it was not discovered. The Shelly integration was just giving me battery state as mentioned previously, what I didnt know is it made some automations available.
What I found was that you can go into configuration > devices and then filter the list to find your shellybutton1-xxxxxxxxx device and click on it, that brings up the device view.
In the device view you get device info, but you also get options to create an automation, scene or script using the button 1. When you create an automation it gives you options for single click, double click, triple click and long press.
After that it is literally as simple as choosing the device you want to control from the list and giving the automation a name.