calling an engneer is hardly worth it , they normally want £50 just to turn up and look at it. The problem is probably that the drive belt snapped or come off , does the motor run but the drum not turn? If so it IS the drive belt . This is very easy to fix , you just take the back off and you should be able to see the drum with the belt round it. If the belt is off or snapped it will be lying inside the dryer but not round the drum, so just put it back on or get a new one and put that on.
The cheapest new driers are around £120 so it is hardly worth paying a repair man £50 call out plus parts and labour.