When my loo blocks it's always a bolckage downstream - the inspection pit outside where the drains all meet - if you have one, take the lid off and look inside. It should be empty. If it has foul water then there will be a blockage on the outlet pointing towards the street.
I clear mine not by trying to push the obstruction down the pipe but by using a stick and pulling the obstruction back into the chamber - usually a ten minute job - better when the weather is cold.
Good luck...
Peccavi, March 2010
