No disk space left despite plenty available

[quids]

To be honest I forgot about it being a btrfs file system initially, but yes it my first attempt at using it instead of Ext4.
After searching around a bit more at btrfs results I'm going to try this out: http://marc.merlins.org/perso/btrfs/...-Problems.html

I'm pulling more data off the SSD in case I have to flatten it. Once its done I'll drop out to a Live CD and attempt the fix

The colourised font was coming straight from bash and Konsole

$ sudo btrfs fi df /
Data, single: total=19.27GiB, used=4.06GiB
System, single: total=4.00MiB, used=16.00KiB
Metadata, single: total=264.00MiB, used=193.48MiB
GlobalReserve, single: total=80.00MiB, used=9.81MiB
$ sudo btrfs fi show /
Label: none  uuid: 3c3f3975-c030-4807-8937-8c848f72ede5
        Total devices 1 FS bytes used 4.25GiB
        devid    1 size 19.53GiB used 19.53GiB path /dev/sda2

[TheFu]

If it hasn't been clear, it appears that both / and /home are mounted to the same partition. THIS IS BAD in your setup. Fix that.

Filesystem      Size  Used Avail Use% Mounted on
/dev/sda2        20G  4.5G     0 100% /
/dev/sda2        20G  4.5G     0 100% /home

See? That ain't good.

Fix that first.

[quids]

I ended up flattening my system and rebuilding with Ext4 this time.
The fault with /home and / being on the same partition has also been resolved