I have a belling cookcentere, and i have experienced this fault twice,the fan is working,but the oven does not heat up,it is usually the element burnt out,this is located behind the cover at the back of the oven.this can be easily removed,please make sure power has been turned off and isolated at fuse board before touching,get an electrician to test the element weather it is open circuit,they will soon tell you weather it is good or bad...any electrical shop will stock these as they are universal,it will cost around the £20 mark....if it not the element then the next thing to check is the thermostat.....hope this helps..
Dean
October 2008