bosch sgs45e02gb/45 dishwasher low water pressure?

Hi,

I got a bosch sgs45e02gb/45 dishwasher. All was OK until yesterday, when everything remained dirty. Have done a bit of digging and wondered if anyone can help me out, cheers.

The water doesn't come through with enough pressure to turn the rotary arms. I stuck a screwdriver in the door sensor and managed to start it on a cycle with the door open to see what was going on. When the water is coming through the top arm it doesn't move, after about a minute it then changes to the bottom arm, after about a 20-30 seconds there is enough pressure to turn the arm but it takes about 20 seconds for a full turn. If I turn it off and back on again the cycle starts from the opposite arm to which it was when I turned it off but this time it turns with full pressure for a full half turn before previous symptoms return. It drains as it should.