How to remove a Joytech freehub (5mm allen key version)
To answer the question, I had to give a sturdy tap to the axel from the back-side (though it looks like you could have gone from either end), which then popped out (leaving me able to remove the bearings) and left (what looks like) the 11mm allen key space to remove the freehub.

Update: you actually need a 12mm allen key (no need for the 11mm at all). You need to use the long part of the allen key (preferable keeping the short end in a vice) to loosen the larger interior receptor (12mm as opposed to 11mm, which is accessible from the drive side)