I also have a Zanussi condenser tumble. Have you ever rinsed through the condenser section? The steam converts to water in this section and over time it fills with lint/hair. If its clogged up it may prevent your machine from working. It's easy to clean, just remove and pour water through it to clear all the lint/hair accumulated, (I use the garden hose as my kitchen sink isn't deep enough to do it properly).
Whilst you have the condenser part removed, use a damp cloth or wet wipe in the slot were the condenser part goes, this will clear any remaining lint that has made it the whole way through the condenser.
I tend to do this once every month or so and use a chopstick in combination with the hoover to get rid of any trapped bits around the door and seals.