I have just moved into a bungalow with one combined bathroom with bath, shower washbasin and WC. I wish to instal a WC and basin into a seperate room replacing a sink in the utility room. The outlets from the sink, washing machine and water softener go into a gulley in the patio which is some 30ft from the soil pipe and manhole for foul waste.Can I convert this gulley to take the toilet waste and can I use a short internal stack pipe to vent the system. What do I need to do to convert the gulley.