While you wait for answers, we may have found some information which could help you.
Click here for Cistern Dual FlushDerwent Macdee metro syphon repair?
cistern constantly fills and runs into toilet pan?
How do we change the flush from 1/2 to a full flush?
my toilet wont flush?
where can I get spares for a Derwent Macdee 9.5 inch round syphon ?
Macdee Metro 3 Part Toilet Syphon?