As a post script, I called Comet and explained the problem to them.
Their advice was that "The manufaturers all now advise that you put the detergent tablet on the cutlery tray now anyway, so you don't need the dispenser draw" :?
They were a little galled when I suggested I'd like it to...
Thanks for that -I'm a dishwasher virgin and initially thought the machine somehow flushed through the detergent container without it opening. I'll give it another try and if no joy get them out to sort it.
I’ve recently purchased a Bosch Excell Aquastar dishwasher (model SMS63E12GB).
I used it a few times and it cleans the dishes well, but after each wash I’ve opened the dispenser draw and the (all in one) tablet is still sitting in its dispenser, largely undissolved except for a corner or...