AEG BB4101-4 Oven faulty thermostat thermocouple?

I’d appreciate some advice please !

I have a faulty AEG B4101 oven PNC 944 185 051 S/N 446 000 98.

The LED shows the time and the red indicator light on the cooking mode illuminates fine but a couple of weeks ago the heating seemed to become temperamental. The cooling fan seemed to stop working at that stage and the control knobs got very hot. Before all of this the lamp had blown maybe a month ago.

I opened up the lid and having looked at this forum saw that the blue plastic capsule had “burnt out”. It was very charred.
On that basis I have now replaced the capsule – Thermal cut out cpl (P/N 899 661 92 67-61/1) (and the internal lamp bulb) but huge dissapointment.

The fault still seems to exist. The temperature indicator light just doesn’t illuminate and there is no sign of life in the oven heating elements.

A couple of immediate questions:
1. Is there any sort of self diagnosis I can follow to identify the fault?
2. Is there another thermostat that could be broken?
3. Is there any thing else you can suggest.

Any help would be greatfully appreciated !
Thanks a lot.

Terry