I have a standard sink trap (not sure on brand) below sink which only the sink and washing machine use. I would like to fit a sink trap with an air admittance valve. I have bought a mcalpine one that I was hoping would have been a like for like replacement (it looks exactly the same) but where it joins to the external black waste pipe in the wall it is slightly too low, maybe by 2CM or so, so the size is obviously slightly different. What options do I have in making it fit? I had a look at solvent welding but I don’t have much space on the straight sections of pipe to fit the connector required for the weld. The part I have bought is called ‘Mcalpine WM2V 1½" Anti -Syphon Sink Trap with Horizontal Nozzle’. Thanks in advance!