The kitchen sink in my second floor flat has always been problematic. It's finally given up the ghost. The setup is the main sink, rinsing sink and dishwasher. I'm guessing the grey flexipipe is the actual waste pipe? I can't see as it disappears down the back. I've tried plunging both sinks (this usually helps with minor blocks). But this time it doesn't really do much - it just pushes water to the other sink. I've tried a couple of products to unblock the sink with no luck. I've taken off the grey flexipipe in the picture and tried a 6ft rod down it, with no luck. When I take off the flexi pipe, water drains fine from the sink out of the white pipe. When I put water down the flexi pipe alone, it holds water. Is this the problem pipe? I've had the dishwasher running to see what happens & the backs up into the sinks. Does anyone have any further DIY recommendations to avoid a call out (money is tight atm).