Hi all, my toilet is driving me mad. As of last week its started hissing (and draining constantly into the bowl) I took the top off to discover its some form of modern toilet do I'm not sure what to do. Initially moving the flapper & float a bit would make it stop until the next flush. However it's been none stop for about 3 days now (I'm glad I'm not on a water meter)! Anyhow please can someone help me out before I go mad?

Pictures: toilet woes - Imgur (yes they are bad I was in a rush)

Thanks in advance!

What brand, I've never seen one like this? You could replace the guts with a standard set if the holes are the same side.