G'day Astrid,
Have you Popped the Top off at all?
Then you might be able to see what / where it is catching.
Often a slight bend / twist will help;
though that was with a Brass Float Arm.
A renew of Seals wouldn't hurt.
One can get Kits to suit the particular Model Cistern.
I do my own
so, you should be able to do yours![]()