So I left my work machine upgrading this evening. When I logged into the VPN to check on it's progress I found a few things stopping it so had to temporarily un-install some packages. Unfortunately I didn't notice the package management tools and ssh get un-installed when I pulled one of their dependencies. Not a place you'll want to be when you have one surviving connection and your cable connection keeps dieing. Luckily I was able to piece together a working system using netcat until I got ssh up and running again. It's useful practise to extricate yourself from a hosed system every now and again just to remind yourself of the low level tools at your disposal. Besides re-installing is a mugs game!