I want to remove a broken dishwasher, but removing the waste pipe needs a waste pipe cap, and I've looked everywhere for the right size. 50mm is too big and 40mm is too small, and there is no size in between, I did buy a 43mm but that turned out to be the same size as the 40mm. This is the thing I bought: 40mm Solvent Weld Access Plug White waste Each new | eBay Am I buying the wrong thing here? It's just the screw cap I need. Either way.. 50mm is too big and 40mm is too small. Should I be buying the push fit caps? But wouldn't the sizes be the same?