I have an AEG D5701-4-m double integrated oven.The fan

Ok this all points to the fan heater element being the fault. As if you have 240v to the fan element but its not heating then its got to be the heater.

I know you say you have replaced the fan element but have you tested it for contonuity with your meter?

Test it and it should read about 28 Ohms.

Check that and see what you find. If its ok then can you post a picture of the back of the oven with the wiring so i can check the wires are in the correct place.

Ok so a bit strange as if you had 240v there then the heater should have come on.

How did you test it? Was it from the tags to earth or tag to tag on the heater?

Ok so if you have 240 on each tag then you have lost the neutral. As there should only be 240v on one side only.

As you have lost the neutral then you need to check the thermal cut out on the back. Look on the back of the oven and there you will see a thermal cut out. It will have 2 wires to it.

Test this for contonuity and see if its faulty. If so then the thermal cut out will need to be replaced from there.

Check that and see what you find and let me know.

No worries thats fine.

Yes still check the thermal cut out as you have lost the neutral feed.

If the thermal cut out is fine just post a picture of the back of the oven so i can see the wires please.

Ive got the pictures thanks.

Looking at the wiring it looks all ok.

As you say the thermostats test ok then it rules them out.

As to the one near the cooling fan this is a open circuit when closes when it gets hot to bring the cooling fan motor on so thats ok is that thermostat.

So as the wiring, fan motor and the thermal cut outs are all fine them im afraid all it leaves is the control board on the top. The relay for the fan element will be faulty which isnt sending the correct power down to the cooling fan. So all you can do in this case is replace the control board im afraid.

Sorry its not looking like good news on this.