Repairs and problems
A toilet that will not flush properly
Weak flushing is either not enough water leaving the cistern, or not enough getting into the pan through the rim.
What actually fixes it
Point 1
A dual flush that has lost its seal drops the effective volume, so the flush never builds momentum.
Point 2
Scaled rim channels in hard water areas restrict the water path around the pan, giving a weak swirl.
Your questions answered
Is a new cistern mechanism the fix?
Often yes on a modern dual flush, especially where the seal is worn.
Can rim scale be cleared?
Partially, with descaling treatments and patience; heavy scale sometimes cannot be fully removed.
Where this fits with our work
Ready to get the room measured up?
Photos of the existing room and the position of the soil stack help enormously before a visit.