Hoover Nextra HNWL 6136 dryer not heating?

I have a washer/dryer and the dryer is not working.

The drum rotates but does not heat up and the clothes are still very damp/wet. Whilst the washer works ok and I've never had a problem with the clothes not being cleaned I'm not sure if it heats up as I've used the setting for 90 degrees and 30 degrees and put my hand on the door and I can't feel the difference. Can anybody help? Thanks