So I tried the MSI utility, it did not fix the issue, I turned off the ram XMP profile which also did not fix it. As a last ditch effort I went into the audio properties and changed sampling frequency from DVD (48khz) down to CD (44.1khz), it took ages to apply as throughout the glitching it felt like the audio device was being unresponsive but after it did it seemed to fix the audio issue. Rebooted twice and audio is still working so fingers crossed its permanent.
Same problem with the Matisse HD Audio Controller, I tried to blacklist in syslinux config to ensure host isn't grabbing it but the VM still crashes the host when I try to start it with this device passed through. I might try again later today and post the startup log to see if someone more knowledgable can pinpoint the issue. It's odd as the card is in it's own group on my Motherboard so I'd think that type of device is easier to pass through.