If its only tripping the electrics on dryer cycle then its more then likely the heater. If you are looking at fixing this yourself then pull the washer out and remove the top panel.
From there you will see the dryer heater chamber on the top. Check the wiring on there and make sure they are all pushed on tight.
If the wires are fine then locate the heater wires and disconnect them and tape them up out the way.
Then set it going on a dry cycle and see if it runs without tripping the electrics. If it does then the dryer heater will need to be replaced from there.
But if its still under warrenty then give Hoover service a bell on 03446 923607 and they will sort it out for you.
If you need anymore info just get back to me.