OK, Problem solved.
There is a thermal fuse under the exhaust fan which had blown. This is a glass fuse with two long leads that terminate in spade connectors; one to the back of the clock and one to the back of the main control knob. It is rated at 167 degrees Centigrade. Checked with a meter it was open circuit and if I used a piece of wire to bypass it, the oven came back to life.
I believe the replacement part is AEG 8996611947525 THERMAL FUSE 611563959, which goes for approx. £18, however getting a replacement locally is a pain - no one seems to carry stock. Local suppliers quoting over 2 weeks as manufacturer doesn't have stock. Some on-line places claim to have it but I was put of by the £12 delivery charge.
However Maplin sell just the fuse - catalogue number RA18U for 69 pence but you have to attach it to the long leads somehow....I chose to solder it as I don't have the necessary crimp tool.
All working fine for now.
Aj
January 2009