How can I remove something that has got through the holes in the drum?

I put some clothing in my Zanussi 1000 Aquacycle washing machine (built in), unfortunately I had not checked the trouser pockets first and I think a something has got through the holes in the drum and is causing the drum to partially wedge, perhaps when the offending item is in a certain position. When the machine is stopped I can rotate the drum and it rotates freely, but I can hear something loose and if I try to rotate the drum in the other direction I can feel it "tightening up" or partially wedging.

How can I access the area to remove the offending item?