So what we had to do was this:
We put the controller in a PC/workstation and booted it into Windows
We downloaded the CLI for the AVAGO megaraid from Dell
We ran the command: perccli /c0 disable directpdmapping=off where 0 is the adapter ID
Then after a reboot we ran: perccli /c0 show directpdmapping
and got:
Controller = 0
Status = Success
Description = None
Controller Properties :
=====================
Ctrl_Prop Value
Directpdmapping OFF
So now we'll try booting the system....