Hi, i have a sewer chamber that is just a single right angle 2 entry with a 320mm inspection lid for rodding. I would like to remove this a fit a chamber with 1 extra inlet. Now all the new chambers i have seen have the main flow at low level & any other inlets at about 2 to 3 inches above. This will throw out the flow on the existing run if i try to fit this chamber. Do they make a chamber with all inlets the same level as the outlet so there is no drop in the chamber.