Ubuntu – Ubuntu changes sound device after suspend, how to fix

So my setup currently is using a monitor plugged into my laptop via HDMI and using the speakers in that for audio not the inbuilt laptop ones. When the machine boots it uses HDMI by default, but I will often suspend the laptop throughout the day and whenever it resumes it switches the sound device to the inbuilt speakers.

It's not a big problem as you can imagine but is annoying, I wonder if there's a script I could use to force it to reselect HDMI after resume or disable the inbuilt speakers, or set as default some how. FYI both the inbuilt speakers are on the same 'sound card' but are two different devices. I use Ubuntu 16.04.