I ended up having a few hours free this evening which I spent in the UDK.

I only sorted out a two things since yesterday, these being:
The floating towers – which I found out was the skeletal mesh having it’s spawn orign set to 0 when it should be minus its height
Spawners pushing out Red blocks – they’re just simple actor which take damage and move towards the player when they get close.

The video also shows the tower shooting but it still has a few targeting bugs which I will need to sort.