Zanussi washer/dryer not drying properly?

Hi there, I have a washer/dryer which does not dry properly any more. After a full drying cycle the clothes will be hot but still quite damp. After another full cycle they will be slightly less damp but not anywhere near dry. Another 1 or 2 full dries eventually gets them dry! I remember from a repair of a previous machine a few years ago that the repair guy cleaned out some kind of plastic tube from the inside of the machine that was full to the brim with gunge. That wasn't the problem he was repairing but that machine too had stopped drying so well. After the tube was gunge free the dryer worked well again. Just wondering how I get into the machine to find the plastic tubey thing? (The filter basket at the bottom is completely gunge free). Many thanks, Georgie