After spotting this thread
I decided it was time I got round to trying to move my filesystem onto my SSD. I used
sudo btrfs replace start -B /dev/mmcblk0p2 /dev/sda1 /
to move the filesystem to a 64gb partition on the SSD and everything seemed to be fine. Then I used
sudo btrfs filesystem resize max /
and the filesystem expanded as expected. Unfortunately a while later and I can no longer access the box via the browser, SSH says No route to host and ping says Destination Host Unreachable. I’ve no idea what happened. Is there any way to recover? Everytime I try something I seem to mess the box up!