Ok so after running up a new droplet with my week old backup and updating to the point that it broke as described. I identified that it was the snapd package (snapd/bionic-updates 2.42.1+18.04 amd64 [upgradable from: 2.40+18.04]) that caused the break.
I then booted via the recovery console and removed the snapd package. I then shutdown and switched back to booting via the standard method and the test system is now working as expected.
I am now going to fully update the test system and reboot.
If this works I will replicate this to my live system.
Edit: This has worked and I have replicated to live system and all is working. The ‘snapd’ package was the issue for me, once removed all was good.