NON FUNCTIONING OF BOTTOM DRAWER DISH WASHER?

Hello Mr Help! Pommieland calling. The bottom drawer of our FP DD503 twin dishwasher is doing strange things and I'm not sure whether or not it needs a repair visit. It is almost 3 years old. It was full and on a heavy cycle. The inital rinse went OK but then it stopped and the central green light flashed in groups of three flashes. We tried to run it again but the same symptoms showed. We turned off the mains power to 'initialise' it, tried again with the same results. We then terminated the cycle, pumped it out opened it. It had certainly rinsed but that's all. We tried it on the next cycle (our normal setting) and it ran for about 30mins appearing to have washed but not completely dried the contents. During the period when we were trying make it work on the heavy cycle, it made a series of strange beeps, none of which are listed in the User Manual. Incidentally, the user manual is for a model DD603 and ours is a DD503. The correct manual does not appear to be available from FP. Regards, Dan