Cistern runs only slowly full?
If it takes forever for the cistern to re-run after flushing, then a rubber is likely to be leaking, causing the inlet valve to not open properly. This happens through limescale and wear.
This rubber sits just behind the inlet connection and is staircase-like and movable, so not just a sealing ring.
I was able to mend the crack with some super glue, now the water is running normally again. So you do not necessarily have to buy a new entry-level machine or at least be able to bridge the weekend until the hardware store is up and running again.
