Martin,
Firefrost Red was introduced by MG Rover. The last 75 built was Firefrost and looks like this:
The 5 millionth Rover was in Xirallic Aubergine - MG Rover built the car and they said in their press announcement:
Thursday, July 10, 2003 – build of the five-millionth Rover, a 75 Saloon, in special Xirallic® Aubergine paintwork (VIN SARRJZLLM4D298618), was celebrated with a visit by The Prince Edward, Earl of Wessex.
Firefrost and Xirallic are different colours as the pctiures show. I'm sure EMS and Wilcox mean well but I have to believe what the manufacturer stated at the time.
Razen Brown was never an MGR Colour, as I'm sure EMS will confirm.
cheers
Mike