Thank you for the extra feedback Isaac! This all makes perfect sense. I'll get reading about exactly what the MBR is now.

So far the laptop has been an absolute dream and I'm really loving Debian

Be aware that (continually) rsync'ing to your backup will give you a backup. Singular.
This is what you asked for, but again may not be what you are (unconsciously ?) hoping for. You can only restore as it was at that time of the last rsync. If you ever want to go back to "last week/month/whatever", you'll need other plans.
rsnapshot as mentioned is a space efficient way of achieving this. Also based on rsync, so might be worth keeping in mind for the future.

As for the MBR, I doubt the value of such backups, but when I do I use sfdisk. Much safer.

You're exactly right, RSYNC'ing is doing what I wanted at the moment but there's no reason not to move forward and use rsnapshot as a longer term solution. Without moving too deep into a discussion on rsnapshot from the brief part I've read it will create snapshots at defined intervals, copying differences from the last backup and hardlinking to files that haven't changed.

If I then wanted to restore I can take what ever folder I wanted an use rsync similar to the ways suggested above to restore the system back?