dryer taking longer to dry?

white knight condenser dryer 0312 76A 15002/21 my dryer is a few years old now but is taking longer & longer to dry stuff recently wen i took the bottom filter thing out to clean it i noticed a small plastic grill thing inside under the drum & theres rubbish thats obviously come out of pockets behind the grill but i cant see a way of getting the rubbish out i dont want to force the grill bit incase i break it but im wondering if this has anything to do with my problem any advice would be greatly appreciated Thanks