Hi derek sorry late not able to post yesterday as lisdar posted but note the bolts and oval plate are very prone to rusting so you may have to replace those as well as doughnut rubber seal while you are doing the job the bolts may have to be sawn out with 12" hack saw blade held in pad handle not sure which syphon you are to re fit but if it is the chamber type with diaphragm then you want to consider using a split type to save you having to take the cistern off the pan in future or best is a new type drop valve that splits as well with button operation when you have it all back together though rest the cistern on to the pan with flush hole into the pan then fill with water then flush to test for operation and any leaks HTH Tez