Hi, my kitchen sink drains very slowly. I have taken all the pipes under the sink and cleaned them but it is still slow so i can only assume the problem is the pipe that takes the waste to the outside drain but i cant get access from the kitchen end due to the kitchen units so the only way is from the outside. My problem is that on the outside there is an l-bend which I cannot get off to rod the pipe out. How do I get the l-bend off please Many thanks, Chris