My Bosch WFF2000 not flushing conditioner?

My Bosch WFF2000 is not flushing all of the conditioner through on the last rinse. I assume that on the last rinse both prewash and main wash valves open on the cold water supply, this then lets enough water into the conditioner compartment. The holes above this compartment appear to be block, I have used a pipe cleaner to try and clean out where the water should come in, but this has not helped. The syphon effect works correctly. How do I clean out the inlet holes?