Page 1 of Wharfedale playing Region 1 discs in black and white

I have just moved house and having reconnected my TV, Wharfedale 750 (first model I think) and amp it now plays the Region 1 discs in black and white.
When the DVD boots up it is in colour, I insert the disc, it shows it is going to play in PAL ((I cannot remember whether they used to be NTSC or not) and then starts playing in B&W.
I am going to try reentering the region code hack tonight, does anybody have any other ideas of what to try.
TIA

To view an NTSC DVD you'll have to use RGB setting. Make sure your scart has the RGB pin connected!