broken toilet cistern

Sounds like it just wants a slight adjustment of the overflow.

Plenty of videos on YouTube in how to do it.

Usually just a turn of the adjustment with your hand.

tried that didn't work think it's a washer issue as in the big one that seals the cistern after flushing .

If it's a modern dual flush toilet there will be 2 adjustments.

One on the inlet float valve & one on the central overflow into the toilet pan.

thanks it's not a dual so can't find tutorial to release the lid 

If the flush button is on top of the lid the button should unscrew then you can remove the lid.

No disrespect to Roland, but he means the circular cap around the button, not button itself (just incase your trying to unscrew the centre button).

Regards

Pauline.

Sorry I did not make myself clear.

I had same query to put those cleaning blocks inside and got told unscrew button, spent ages trying in frustration and by chance as it was little loose then discovered the outer collar. Just saying!!

No offence meant Roland.

Pauline.

Try Richard at R1 Plumbing, see pic