Help me diagnose the problem with my oven...

[chippednailvarnish]

I have an Electrolux Gusto range cooker and for some reason the large oven cooks food more on one side than the other. The photo is of some cupcakes I baked tonight, as you can see some are burnt.

I have taken the fan cover off and it is operating, so before I call someone out to look at it, has anyone got any ideas?

I think you get this with cheaper ovens. Electrolux are not what they were.

I've just replaced one of their dishwashers and the difference is night and day.