One idea I had was to create one model that was quite complex and intricate and then model the various levels of it's destruction based on which area was hit. I decided this would be a massive pain to create and manage the assets.
I then thought I might just make it as simple as I can and make it look like a "spaceship-esque" wall made up of metal "bricks". This would make things much more simple in terms of the collisions as I would just destroy one brick when it was hit. This is the approach I decided to stick with, as it was a nice fit with my blender skills at the moment.
Here is a screenshot of me trying to work out how to use blender for even this simple model:
The only thing I did have to change was the collision filtering, I had to put in extra rules for this new "DefencePostBox" Entity. Now whenever a "DefencePostBox" is hit by a projectile they will both be destroyed. This means that even the player can accidentally destroy their own defence posts.
I'm fairly happy with the progress for the couple of hours I've worked on this tonight, here is a video of the results. (Oh I've also been messing around with the screen resolution so the enemies currently go off screen).
I'm not quite sure what is next on the cards but I'm really excited with the progress so far :)