I have a 1930's house with separate toilet and bathroom. I want to knock through to create a larger single bathroom. To get the space I need for a shower, I need to turn the toilet 90 degrees. This will mean having to direct the waste 90 degrees horizontally towards the external wall. IS this Ok and how much distance will I need to have the toilet away from the wall in order to allow enough space for the horizontal u-bend to work OK.