I have had this happen in the past.
I removed the entire toilet from it's place in the bathroom (not as difficult as it sounds. One supply pipe, an 'overflow' pipe, and a couple of screws holding the cistern to the wall and the base to the floor) and then poured sulphuric acid drain unblocking liquid down the soil pipe.
A bit of bubbling and some noxious gases and 'bingo', all cleared through.
However the removal of the fittings is a bit of a pain.
And the acid is not easy to get hold of.
Most 'rodding' tools are not very flexible so don't cope well with the tight bends of the soil pipe, or the toilet pan itself.
A more user-friendly item is the 'monument pipe unblocker' which is a flexible thick steel wire with a twisty hook thing on the end. You introduce it to the pipe, reel it out until it hits the blockage, then start turning the handle (pic underneath).
Also, more modern properties will have drainage which incorporates an inspection panel in the 'elbow' joints on the pipes, so you can unscrew a small part and introduce your tool (oo-er) from there instead.
I removed the entire toilet from it's place in the bathroom (not as difficult as it sounds. One supply pipe, an 'overflow' pipe, and a couple of screws holding the cistern to the wall and the base to the floor) and then poured sulphuric acid drain unblocking liquid down the soil pipe.
A bit of bubbling and some noxious gases and 'bingo', all cleared through.
However the removal of the fittings is a bit of a pain.
And the acid is not easy to get hold of.
Most 'rodding' tools are not very flexible so don't cope well with the tight bends of the soil pipe, or the toilet pan itself.
A more user-friendly item is the 'monument pipe unblocker' which is a flexible thick steel wire with a twisty hook thing on the end. You introduce it to the pipe, reel it out until it hits the blockage, then start turning the handle (pic underneath).
Also, more modern properties will have drainage which incorporates an inspection panel in the 'elbow' joints on the pipes, so you can unscrew a small part and introduce your tool (oo-er) from there instead.