Thanks!
Got my order of MDF but it's not cutting very well, not sure if it's the laser or if it's the MDF, it's quite fussy if the MDF is too dense it doesn't cut very easily and there is no way to tell. Looks like I've been unlucky.
Started on the other tower and wing just because I've got other stuff to do (domestics) and I can leave it cutting.
I also rigged up a cooler for the Laser water, MG-B heater matrix and some case fans!
Pics to follow...