While you wait for answers, we may have found some information which could help you.
Click here for Cistern Dual Flushmy toilet wont flush?
Toilet seat?
where can I get spares for a Derwent Macdee 9.5 inch round syphon ?
Derwent Macdee metro syphon repair?
Macdee Metro 3 Part Toilet Syphon?
cistern constantly fills and runs into toilet pan?