I've dismantled the top of the cooker to reveal the control and manged to get the switch unit working again, but only temporarily as part of it is burnt out.
I have ordered a replacement from cooker -parts.co.uk for £57.50. part No.PMSMG811730118.
It will be quite easy to fit, but you need to mark the incoming cables and where they are located onto the switch, to ensure they go back correctly.
Best of luck Joe
Joe Schneider, April 2012