Bosch Wfa1000 Draining Slowly, Most Likely Blocked With Hair

Hi everyone, since my girlfriend, who has long hair that seems to get stuck in everything, has moved in, our washing machine has become increasingly bad at draining, most times clothes are still sopping wet after the final cycle, but recently, the door has remained locked, presumably because the drum is still too full of water.

Can someone give me a walkthrough of which parts to check for blockages, or is this a task for a proper repair technician?