How can I fix my leaking loo cistern?

My Ideal Standard toilet cistern was filling very slowly and I unscrewed the ball cock to see if there was some obstruction. When I replaced the ballcock float (inserting the rubber washer/grommet correctly I think - it will only go one way because of a 'spike' on one side) the cistern won't stop filling and the overflow continuously leaks into the toilet bowl.
How can I fix this?
Tim Pearson, July 2005


done
Dishwasher goes bang 2/3 way thru cycle and stops working.

emma, March 2011
lower the ballcock untill it stops, then leave at that level.......simples....

emma, March 2011
my toilet is leaking from where the flush pipe fits into the toilet. how do i stop yhe leak?

Lee Sears, May 2010