I have now investigated the problem with the same model of Microwave Oven and found that the yellow wire connector at the base of the Magnetron the crimp connection was high resistant and showed signes of getting hot, which stopped the magnetron working. I have replaced the spade connector with a new one and it is now perfect. You can replace the Magnetron if it is faulty with a Panasonic 2M210-M1 Magnetron, the cost is approx £40 delivered.
L H Capewell, April 2008