Dual Flush toilet intermittently running

[Kaytip]

My dual flush loo starts running sometimes (but no means all the time) after a flush. Sometimes its a thin stream, other times a bit less. I've left it without the cistern lid for a few days at a time, and it doesn't seem to happen then. It only seems to happen when the chrome flush is on, or alternatively I've tried it with the round chrome mechanism screwed down but not the actual chrome buttons, and it has done it then as well. I'm wondering if it's the flush mechanism sticking, and if so, what I can easily try to remedy this. It's a fairly new loo (less than 6 months).
Thanks so very much for any help.
I've attached some pics (I think - this is my first time on this forum!)

 

[tincup]

Hi

It maybe the rods that operate the mechanism are lifting the flushing valve very slightly of its seat when the lid is fitted.

 

[Charnwood]

View media item 63591
View media item 63592
View media item 63593

 

[Kaytip]

Thank you to Charnwood for putting the pics on the message for me.

It maybe the rods that operate the mechanism are lifting the flushing valve very slightly of its seat when the lid is fitted.

That would make sense - any idea what I could do about this?