A few days before and after the full moon have been the best days for myself. The day of the full moon has been tough in my experiences. By the way, I never saw you mention that all of the fish you are catching came from the same spot. Bream can be caught in shallow water, close to the bank almost all the time, that doesn't mean it's a bed or they are spawning. You know it's a bed when you can see the bowl shaped beds (if the water is clear enough), you are catching multiple fish in the exact spot, and the males will piss when you squeeze them.