While you wait for answers, we may have found some information which could help you.
Click here for Toilet Repair Mechanism
twyfords close coupled toilet 40 years old?
i dont have a ballcock in the cistern, how do i fix the overflow? ?
twyfords toilet cistern?
running cistern?
removing lid of a twyford dual flush cistern?
Twyfords close coupled toilet with plastic thing leaks between pan & thing?