Candy IWDC65125UKN washer dryer

Its an Indesit model number not a Candy!
Best bet is to turn power off, whip the lid off, pull both wires off the dryer heater AND PUT TAPE around each separate terminal tag to isolate them apart- woe betide if the bare tags touch something that they should not = bang!, then turn on to dry and see if water then comes into machine****. If it water now doesn`t you need a new dryer element to cure the problem. If no difference the main pcb has snuffed it which is more common- Indesit only changeable due to having to be programmed on site. Should be under a 10 year parts warranty especially if you registered the purchase which I hope you did. Think their labour is 139 quid now which is still cheaper than a new board however a 139 quid bill is still quite depressing.
You should know that for a couple of seconds the water valve is triggered anyway so hope you know that but never-the-less the flashing lights business is a fault code.
**** note if water comes into the machine via the dryer section of the valve “cluster” so presume you mean the valve is triggered and fills as though it is on a wash /or rinse programme i.e. it gushes in through via the soap box. If it doesn`t gush in through the soap box the dryer valve restricter has detached itself from inside the valve – not unknown but not common in which case you need a new valve. Hope this makes sense.