Drying programmes on Indesit Washer Dryer IWDE12?

Have been using Indesit Washer Dyer IWDE12 for some months but only as washing machine. Have now used dryer for first time for line-dried but still damp items. Set for 40 minutes on programme 7 (cottons). Dryer was running for longer than 40 minutes so switched off at plug. When door unlocked, clothes were dry but very hot so I guess it hadn't started a cool-down. Why did it take longer than 40 min and is the cool-down period in addition to this anyway? How accurate should I expect the time dial to be? And how do I get the dispenser tray out to clean it? Thanks!