You need to replace the thermostats above the heating element. Mine had the same problem. Easy repair in minutes.
To check, turn off power. Remove the RED DOT thermostat and connect the 2 spade connectors together. Switch on power.
If the heating elemnet is working - replace the STATS and your fixed.
Be careful where you obtain these parts as some places charge over the odds.
Cost to repair about £12.
Chris L, April 2007