hi i think i need to replace all the waste pipes under the sink. I need to find replacements for d/w and w/m as when my partner fitted waste for these i realised that water from drain and from w/m were in fact going into my d/w. my partner then went out and brought a part which stopped the water coming out of the pipe in both waste for d/w and w/m but when he did this he had to add lots of different segments to make the plastic piping join onto the new part ?????? no i don't understand either.but now the d/w waste is leaking so i was thinking maybe i should just start again from scratch but would still need the special part to stop water from entering the d/w or w/m. any ideas on what i would need to complete this job and what would be the best parts to get. please help as i cannot use any appliances until this is sorted. many thanks