A quick update
The dealer said the unit was kaput and C4 wouldnt repair it. They also said it was out of Warranty.
I decided to contact C4 directly and they agreed to honour their new 3 year warranty. They are now sending us the new triad Amp.
Absolutely amazing customer service
I wont give them a hard time I need there help.
The rack is in a fair sized room and has fan units and vent panels in.
The only other ventilation is the trickle vents in the windows.
I will post an update after they have visited.